HomeMy WebLinkAboutGeotechnical Evaluation May 6, 1998� P E T R A
COSTA MESA • SAN DIEGO • TEMECULA • LOS ANGELES
' May 6, 1998
J.N. 163-98
'
US HOME
4371 Latham Street, Suite 204
'
Riverside, California 92501
Attention: Mr. Mark Pearce
Subject: Geotechnical Evaluation, Tracts 23066-5 and 23067, Redhawk Area,
Riverside County, California
Petra Geotechnical, Inc. is pleased to submit herewith our geotechnical investigation
report for the proposed residential developments to be built in the Redhawk
Development in the County of Riverside, California. This work was performed in
accordance with the scope of work outlined in our Proposal No. 1156-98 dated
' February 9, 1998. This report presents the results of our field investigation, laboratory
testing and our engineering judgement, opinions, conclusions and recommendations
pertaining to geotechnical design aspects of the proposed development.
' It has been a pleasure to be of service to you on this project. Should you have any
questions regarding the contents of this report or should you require additional
' information, please do not hesitate to contact us.
1
Respectfully submitted,
PETRA GE(
' FETRA 6_OTECHNICAL INC
_7020 Commerce Center Dr Ste 103
Temecula. CA 92590
' Tel: (909) 699-6193
Fon (90 9) 699-6197
Petrate@ibm net
INC.
t4) Addressee
(2) Redhawk Acquisitions
Attention: Mr. Steve Ford
' US HOME May 6, 1998
TRs 23066-5 & 23067/Redhawk J.N. 163-98
Page i
tTABLE
DE -('OATEN -TS,
'
Sactian
Page
INTRODUCTION..................................................
1
'
Location and Site Description ......................................
1
INVESTIGATION AND LABORATORY TESTING ......................
3
Aerial Photograph Analysis .......................................
3
'
Literature Review ...............................................
4
Field Exploration ...............................................
4
'
Laboratory Testing ..............................................
5
FINDINGS........................................................5
Regional Geologic Setting ........................................
5
'
Local Geology and Soil Conditions .................................
5
'
Groundwater...................................................
6
Faulting.......................................................
7
'
Seismicity.....................................................
7
Seismic Design Considerations .................................
8
Secondary Effects of Seismic Activity ...........................
8
'
Liquefaction...................................................
9
Landsliding....................................................
9
CONCLUSIONS AND RECOMMENDATIONS ........................
10
General......................................................
10
Earthwork.................................................10
General Earthwork and Grading Specifications ..... . ............
10
Clearing and Grubbing......................................10
'
Excavation Characteristics ...................................
11
Groundwater ..............................................
I1
Ground Preparation - Fill Areas ...............................
11
'
Canyon Subdrains..........................................13
Disposal of Oversize Rock ...................................
13
Fill Placement.............................................13
'
Benching .................................................
13
Processing of Cut Areas .....................................
14
Cut/Fill Transition Lots ......................................
14
'
Slope Construction .............................................
15
Stability Calculations ........................................
15
CutSlopes ................................................
Fill Slopes
15
................................................15
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US HOME
May 6, 1998
TRs 23066-5 & 23067/Redhawk
J.N. 163-98
Page ii
TABLE OF CONT NT (Continued)
'
Fill Above Cut and Cut to Fill Transition Slopes ..................
16
Slope Landscaping and Maintenance ...............................
17
'
Landscaping For Cut and Fill Slopes and Surficial Erosion ..:.......
18
Natural Slopes .............................................
19
Settlement Monitoring Considerations ..............................
19
'
Shrinkage, Bulking and Subsidence ................................
20
Geotechnical Observations .......................................
21
Post -Grading Considerations .....................................
Utility Trenches ............................................
21
21
Lot Drainage ..............................................
22
'
Tentative Foundation Design Recommendations ......................
Footing Setbacks From Descending Slopes ......................
23
23
Building Clearances From Ascending Slopes .....................
23
Expansive Soil Considerations ................................
25
'
Atterberg Limits...........................................30
Footing Observations ........................................
31
Soluble Sulfate Considerations ................................
31
'
Foundation Design Parameters ................................
31
'
Construction On Level Ground ................................
32
Construction On Or Near Descending Slopes .....................
32
'
Lateral Earth Pressures ......................................
32
Drainage..................................................33
Waterproofing .............................................
......................
33
Backfill..................................................33
Concrete Flatwork..........................................
34
'
Masonry Block Garden Walls .....................................
34
GRADING PLAN REVIEW AND CONSTRUCTION SERVICES ..........
35
INVESTIGATION LIMITATIONS ...................................
35
' References
Plates 1 and 2- Geotechnical Maps (in pocket)
' Appendices
Appendix A - Logs of Borings and Trenches
Appendix B - Laboratory Test Criteria/Laboratory Test Data
Appendix C - Standard Grading Specifications
Appendix D - Slope Stability Calculations
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US HOME
TRs 23066-5 & 23067/Redhawk
1
GEOTECHNICAL EVALUATION
' TRACTS 23066-5 AND 23067, REDHAWK
AREA, RIVERSIDE COUNTY, CALIFORNIA
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May 6, 1998
J.N. 163-98
Page 1
This report presents the results of Petra Geotechnical, Inc.'s (Petra's) geotechnical
investigation of the subject property. The purposes of this investigation were to
determine the nature of surface and subsurface soil conditions, to evaluate their in-
place characteristics and to provide geotechnical recommendations with respect to site
grading and for design and construction of building foundations. This investigation
also included a review of published and unpublished literature and geotechnical maps
pertaining to active and potentially active faults that lie in proximity to the site and
which may have an impact on the proposed construction.
Lncatio"nd- ite-Dmription
The subject site, which is currently undeveloped, is located on the southeast side of
Nighthawk Pass (southwest of Butterfield Stage Road) and on the east side of
Redhawk Parkwav for a distance of approximately 1,600 feet southwest of El Chimisal
Road within the Redhawk Development, east of the City of Temecula, California. The
irregular-shaped property consists of drainage ways and grass -covered hills of
moderate relief.
Elevations vary from approximately 1,207 feet above sea level northeast of the
intersection of Redhawk Parkway and El Chimisal Road, to approximately 1,335 feet
above sea level near the northeastern portion of the site. Gradients on the site range
from 13:1 to 1.5:1 (horizontal: vertical [h:v]) or steeper. Drainage is generally towards
the northwest.
Underground structures known to be present within the site consist of a waterline
along El Chimisal Road.
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Vegetation within the site consists of grasses, small shrubs and cacti.
The site is bordered on the northwest by Nighthawk Pass and Redhawk Parkway, on
the northeast by vacant land, on the southeast by citrus groves and on the southwest
by a graded -residential tract. The general location of the site is shown on Figure 1.
Proposed4eYelopmentLOr_ading
The enclosed 100 -scale conceptual grading plans, prepared by Rancho Pacific
Engineering for Tentative Tract 23066-5 and Hunsaker and Associates for Tentative
Tract 23067 (Plates 1 and 2), indicates that the proposed development will consist of
517 finish -graded pads for construction of single-family residences and associated
slopes and access streets. Open -space lots designated along the southerly and easterly
tract boundaries will remain ungraded.
Maximum proposed cuts and fills from original topography are approximately 43 and
40 feet, respectively. Maximum proposed cut -slope height is approximately 40 feet
at a gradient of 2:1 (h:v) and maximum proposed fill -slope height is approximately 60
feet at a gradient of 2:1 (h:v).
P-urp-a eand-Scop€ofSerYices
The purposes of this study were to: (1) obtain information on the subsurface conditions
within the project area; (2) evaluate the data; and (3) provide conclusions and
recommendations for design and construction of the proposed structures as influenced
by the subsurface conditions.
The scope of our investigation consisted of:
• Review of available published and unpublished data concerning geologic and soil
conditions within and adjacent to the site that could have an impact on the
proposed development. This included review of data acquired by other engineering
firms for adjacent properties (see References).
T.ea�3oly� 'si
7.e (;:2 v
' INV STLGATLON AND—LAI-ORATORY TESTING
Ae.rial-PULagraph_Aaalysis
' Sequential stereo aerial photographs covering the site area were reviewed and analyzed
' by Petra for the years 1962 and 1995. These photographs, obtained from Riverside
County Flood Control, are at scales ranging from 1 inch equals 1,600 feet to 1 inch
' equals 2,000 feet.
US HOME May 6, 1998
TRs 23066-5 & 23067/Redhawk J.N. 163-98
Page 3
• Review and interpretation of stereo and oblique aerial photographs dating from
'
1962 and 1995.
• Geologic mapping of the site.
• Excavation, logging and selective sampling of five borings to depths of up to 41
feet. Boring locations are shown on Plates 1 and 2 and descriptive logs are given
'
in Appendix A.
• Excavation, sampling and logging of 45 test pits to acquire soil samples for
'
laboratory testing and to evaluate geologic structure and lithology. Test pit logs are
given in Appendix A and the locations of these pits are shown on Plates 1 and 2.
• Laboratory testing and analysis of representative samples (bulk and undisturbed)
obtained from the borings and test pits to determine their engineering properties.
'
Laboratory test criteria and test results are presented in Appendix B.
• Preparation of geotechnical maps (Plates 1 and 2) and geologic cross-sections
through critical areas of proposed grading with respect to interpolated and
extrapolated geologic conditions (see Figures 2 and 3).
'
• Engineering and geologic analysis of the data with respect to the proposed
development.
'
• An evaluation of faulting and seismicity of the region as it pertains to the site.
• Preparation of this report presenting our findings, conclusions and
'
recommendations for the proposed development.
' INV STLGATLON AND—LAI-ORATORY TESTING
Ae.rial-PULagraph_Aaalysis
' Sequential stereo aerial photographs covering the site area were reviewed and analyzed
' by Petra for the years 1962 and 1995. These photographs, obtained from Riverside
County Flood Control, are at scales ranging from 1 inch equals 1,600 feet to 1 inch
' equals 2,000 feet.
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' Associated with the subsurface exploration was the collection of bulk samples and
relatively undisturbed samples of soil and bedrock materials for laboratory testing.
' Undisturbed samples were obtained using a 3 -inch -outside -diameter modified
California split -spoon soil sampler lined with brass rings. The soil sampler was driven
' mechanically with successive 30 -inch drops of a gravity -driven, 140 -pound hammer.
The central portions of the driven -core samples were placed in sealed containers and
' transported to our laboratory for testing.
Several test pits and borings were previously excavated within the site in 1989 under
the direction of Petra (References). Approximate locations of these previous test pits
' and borings are also shown on Plates 1 and 2.
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US HOME May 6, 1998
TRs 23066-5 & 23067/Redhawk
J.N. 163-98
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Litet','1 �r Revie3Y
Various in
geotechnical reports and geologic studies proximity to the site were
reviewed and are listed in the Reference Section (attached).
'
FieldExpinration
'
Subsurface exploration was performed on February 21, March 4 and 5, 1998 and
involved the excavation of 45 test pits to depths ranging from 3 to 11 feet utilizing a
track -mounted backhoe. A hollow -stem drill rig was used to drill five exploratory
'
borings to depths varying between 21 and 41 feet. Yellow "caution" tape was placed
within the trench excavations and the trenches were then backfilled. Borings were
'
backfilled and tamped.
Approximate locations of the test pits and exploratory borings are shown on Plates 1
'
2. Descriptive logs
and are presented in Appendix A.
' Associated with the subsurface exploration was the collection of bulk samples and
relatively undisturbed samples of soil and bedrock materials for laboratory testing.
' Undisturbed samples were obtained using a 3 -inch -outside -diameter modified
California split -spoon soil sampler lined with brass rings. The soil sampler was driven
' mechanically with successive 30 -inch drops of a gravity -driven, 140 -pound hammer.
The central portions of the driven -core samples were placed in sealed containers and
' transported to our laboratory for testing.
Several test pits and borings were previously excavated within the site in 1989 under
the direction of Petra (References). Approximate locations of these previous test pits
' and borings are also shown on Plates 1 and 2.
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' US HOME May 6, 1998
TRs 23066-5 & 23067/Redhawk J.N. 163-98
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LaboratoryTesting
' Maximum dry density, expansion potential, soluble sulfate analysis and consolidation
characteristics were determined for selected disturbed (bulk) and/or undisturbed
' samples of soil and bedrock materials considered representative of those encountered.
Moisture content and unit dry density were also determined for in-place soil and
bedrock materials in representative strata. A brief description of laboratory procedures
' and summaries of the test data are presented in Appendix B. An evaluation of the test
data is reflected throughout the Conclusions and Recommendations Section of this
' report.
' EINDJNGS
Regima LG-enlagic-S_etting
I' The site is located within the Peninsular Range Geomorphic Province of California.
1 The Peninsular Ranges are characterized by steep, elongated, northwest -trending
valleys. More specifically, the site is located in the southern (Temecula Basin) portion
' of the Perris Block. The Perris Block is bounded on the north by the San Gabriel and
Cucamonga faults, on the east by the San Jacinto fault, on the west by the elsinore
trough and on the south by an undefined zone south of Temecula. The Perris Block
is predominantly composed of crystalline granitic basement complex of Cretaceous
age with Quaternary sediment accumulation in low-lying areas. The crystalline
basement and Quaternary Pauba sandstone form well-rounded hills of moderate relief.
' Sparse volcanic units of Tertiary age occur in the western portion of the Perris Block.
' LocaLGeolagy_and_SoiLCmditiom
Locally, the soils exposed on the site consist of artificial fill, recent alluvium,
' colluvium and cuts exposing ut Quaternary Pauba sandstone. Several trenches
revealed a reddish brown, coarse-grained clayey sand laver overlying the Pauba
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US HOME
TRs 23066-5 & 23067/Redhawk
May 6, 1998
J.N. 163-98
Page 6
sandstone. Kennedy (1977) mapped this unit as Quaternary terrace near the site. We
have included this terrace in the Pauba Formation for this study.
Artificial Fill (man symbol: Aft -- Artificial fill is located beneath EI Chimisal
Road that consists primarily of silty sand covered with layers of gravel.
Recent Alluyium_(map symbol - Qat) -- Recent alluvium was observed within the
drainages in areas of low relief. It typically consists of tan to dark brown, well -
graded sand which was found to be dry to wet and loose to medium dense with
moisture and density increasing with depth. Thicknesses were observed to range
from 3.5 to 30 feet.
Qu_atemary—C'olstyitt_m (man symbol. Qcoll -- Quaternary colluvium was observed
throughout the site on the tops and flanks of hills. It ranges in thickness from I
foot to 9 feet. The colluvium is typically dark brown silty to clayey coarse-grained
sand with occasional cobbles. It was very moist to wet and commonly loose.
' Qt att temaryPauba Formation—(Map sy mboL Qns) -- The Quaternary Pauba
Formation (Pauba) underlies the site at depth. An area of cut Pauba is exposed in
an old borrow area in Tract 23066. The Pauba Formation encountered onsite was
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consisted of coarse-grained, poorly graded orange sandstone which was moist,
well -indurated, friable and dense and a yellow to grey silt unit which was slightly
damp to wet, well -indurated and dense; a third unit consisting of a yellow -grey,
coarse-grained, poorly graded sand was observed northeast of El Chimisal Road.
The sand was nonindurated wet and dense. The orange sand and yellow silt unit
is commonly interbedded. As noted above, reddish brown clayey sand commonly
overlies the Pauba. This soil was moist to wet and generally medium dense.
Landslide.(map_symhoLQls) -- One area of ancient landslide debris is present near
the east side of El Chimisal at Redhawk Parkway. The landslide mass is highly
eroded and similar to the secondary colluvium.
Grown Yater
Seepage was encountered in several of our test pits at depths of 2 to 5 feet, due to
recent heavy precipitation. The water was observed to be flowing atop the clayey sand
layer. Groundwater was encountered in three of our borings at depths of 4, 10 and 25
feet below the ground surface.
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TRs 23066-5 & 23067/Redhawk
May 6, 1998
J.N. 163-98
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Flowing water was observed within the natural drainages and standing water was
observed in low-lying areas adjacent to Redhawk Parkway and Nighthawk Pass at the
time of our investigation.
Eaulting
The geologic structure of the entire southern California area is dominated mainly by
northwest -trending faults associated with the San Andreas system. Faults such as the
Newport -Inglewood, Whittier, Elsinore, San Jacinto and San Andreas are major faults
in this system and all are known to be active. In addition, the San Andreas, Elsinore
and San Jacinto faults are known to have ruptured the ground surface in historic times.
Based on our review of published and unpublished geotechnical maps and literature
pertaining to site and regional geology, the closest and most significant active fault
to the site is the Wildomar branch of the Elsinore fault zone located approximately 2
miles to the west.
No other active or potentially active faults project through or toward the site and the
site does not lie within an Alquist-Priolo Special Studies Zone.
Seismicity
The maximum credible earthquake for a particular fault is the largest magnitude event
that can reasonably be postulated to occur based upon existing geologic and
seismologic evidence independent of time. Most maximum credible earthquakes
generally cannot be assigned a meaningful probability of occurrence, which is usually
very low over the useful design life of most construction.
Based on our study, the Elsinore fault zone appears capable of generating the most
severe ground shaking at the site with a maximum credible magnitude of 7.5 on the
Richter scale.
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TRs 23066-5 & 23067/Redhawk
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J.N. 163-98
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Estimated peak site ground acceleration from a magnitude 7.5 earthquake on the
Elsinore fault zone, should an event occur opposite the site, is on the order of 0.602
(Campbell and Bozorgnia, 1994). In some cases, for design purposes, the repeatable
acceleration can generally be used. This is considered to be equal to approximately
two-thirds the peak acceleration, thus: 67% x 0.6028. = 0.403g.
The property will probably experience ground shaking from at least small to moderate
size earthquakes during the life of the proposed structure. Furthermore, it should be
recognized that the southern California region is an area of moderate to high seismic
risk and that it is not considered feasible to make structures totally resistant to seismic
related hazards. The accelerations previously mentioned are presented for your
consideration; however, the design acceleration should be determined by the structural
consultant and be reflective of the type of structure proposed. Design in accordance
with the current Uniform Building Code (UBC) and the seismic design parameters of
the Structural Engineers Association of California is expected to satisfactorily mitigate
the effects of ground shaking.
For seismic design (UBC Section 1627.2), the site should be assigned to Seismic
Zone 4 per UBC Figure 16-2 of the 1994 UBC and a seismic zone factor (Z) of 0.4
should be used per UBC Table 16-I. Based on site geology and subsurface soil
characteristics (UBC Section 1627.3), soil profile S„ as defined by UBC Table 16J,
is representative of the site. A site coefficient (S) of 1.2 is considered appropriate for
design of the structure.
.s. M • ION.]u
Secondary effects of seismic activity normally considered as possible hazards to a site
include several types of ground failure as well as induced flooding. Various general
types of ground failures which might occur as a consequence of severe ground shaking
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TRs 23066-5 & 23067/Redhawk
May 6, 1998
J.N. 163-98
Page 9
of the site include landsliding, ground subsidence, ground lurching, shallow ground
rupture and liquefaction. The probability of occurrence of each type of ground failure
depends on the severity of the earthquake, distance from faults, topography, subsoils
and groundwater conditions, in addition to other factors. All of the above secondary
effects of seismic activity are considered unlikely at the site.
Seismically induced flooding which might be considered a potential hazard to a site
normally includes flooding due to a tsunamis (seismic sea wave), a seiche or failure
of a major reservoir or retention structure upstream of the site. Since the site is
located nearly 25 miles inland from the nearest coastline of the Pacific Ocean at an
elevation in excess of 1,200 feet above mean sea level, the potential for Seismically
induced flooding due to a tsunamis run-up is considered nonexistent. Since no
enclosed bodies of water lie adjacent to the site, the potential for induced flooding at
the site due to a seiche (i.e., a wave-like oscillation of the surface of water in an
enclosed basin that may be initiated by a strong earthquake) is also considered
nonexistent.
Liquefaction
Liquefaction is not considered likely because all alluvial soils will be removed and
replaced with properly compacted, granular heterogeneous fill.
1°ossiblel.andslidin g
Future landslides are not likely due to the removal of hill and valley topography typical
of landslide areas during grading. Furthermore, no surrounding hillsides have the
potential to fail on the site.
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CONC 1i I SIGNS AND RECOMME �DATIONS
' GsReral
' From a soils engineering and engineering geologic point of view, the subject property
is considered suitable for the proposed residential development provided the following
' conclusions and recommendations are incorporated into the design criteria and project
specifications.
Earthwork
GgmemU arth3y�ark-and_G radingSp_ecifications
' All earthwork and grading should be performed in accordance with all applicable
requirements of the Grading of the County of Riverside, California, in addition to the
' provisions of Appendix Chapter A33 of the 1994 UBC. Grading should also be
performed in accordance with applicable provisions of the attached Standard Grading
' Specifications (Appendix C) prepared by Petra, unless specifically revised or amended
herein.
' Clearingand Gruhbing
'
All weeds, grasses, shrubs and cacti in areas to be graded should be stripped and
hauled offsite. During site grading, laborers should clear from fills any roots and other
'
deleterious materials missed during clearing and grubbing operations.
The project soils engineer or his representative should be notified at the appropriate
'
times to provide observation and testing services during clearing operations to verify
compliance with the above recommendations. In addition, any buried structures or
'
unusual or adverse soil conditions encountered that are not described or anticipated
herein should be brought to the immediate attention of the geotechnical consultant.
'
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ExcaYationSharacteris-tics
Based on the results of our exploratory borings and test pits, suificial deposits of
colluvium, alluvium and fill will be readily excavatable with conventional
earthmoving equipment. Most Pauba bedrock and terrace -deposit materials will be
excavatable with moderate to heavy ripping.
Groundwater
Groundwater was encountered at depths of 4 to 25 feet below ground surface within
borings drilled in the low-lying areas on the site and seepage was observed in most
test pits at depths of 2 to 5 feet. The effects of groundwater on proposed grading are
discussed in the following section.
GxQund-fteparation---FAR-Ax-ea s
All existing low density and potentially collapsible soil materials, such as loose
manmade fill, colluvium, alluvium, landslide debris and highly weathered bedrock,
will require removal to underlying dense bedrock or dense native soils from each area
to receive compacted fill. Dense native soils are defined as undisturbed native
materials with an in-place relative compaction of 85 percent or greater based on ASTM
D1557-91. Prior to placing structural fill, exposed bottom surfaces in each removal
area should be scarified to a depth of at least 6 inches, watered or dried as necessary
to achieve near optimum moisture conditions and then recompacted in-place to a
minimum relative density of 90 percent.
Based on test pits, borings and laboratory testing, anticipated depths of removals are
shown on the enclosed geotechnical maps (Plates 1 and 2). However, actual depths
and horizontal limits of removals will have to be determined during grading on the
basis of in -grading observations and testing performed by the project soils engineer
and/or engineering geologist.
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Groundwater will be encountered at depths of approximately 4 to 25 feet during
removal of the alluvial deposits on the north and south sides of El Chimisal Road. For
these areas, we present the following alternative recommendations for your
considerations.
A dewatering program could be implemented to lower groundwater levels to depths
that will allow complete removal of the alluvial deposits to competent bedrock. A
suggested dewatering system consists of uniformly spaced dewatering wells with
perforated pipe (encased in gravel), extending 1 to 3 feet into bedrock. Continuous
pumping of the wells on a 24-hour basis using pumps of sufficient capacity will be
required to effectively lower the groundwater levels.
A second alternative consists of removing the alluvial soils to depths of 1 to 2 feet
above the groundwater levels and placing compacted fills to proposed finish
grades. A settlement monitoring program should then be implemented to evaluate
post -grading settlement of the alluvial soils left in-place below the compacted fills.
If this alternative is followed, construction of residential structures and
underground utilities on lots and streets that may be influenced by post-grading-
settlement
ost-gradingsettlement of the alluvial soils should be delayed until survey monitoring data
indicate that primary settlement has occurred and that future long-term or
secondary settlement will not adversely affect the proposed structures or
underground utilities. Recommendations for installation of settlement monuments
are provided in a following section.
• Minimal removal of alluvial soils was performed prior to placing the road fill along
' El Chimisal Road. Therefore, regardless of which alternative is used to remove the
alluvial deposits on the north and south sides of El Chimisal Road, there exists a
relatively high-risk for settlement of the existing road fill and subsequent damage
to the waterline during grading; therefore, a third alternative consists of temporarily
rerouting the existing waterline and removing the road fill and alluvial soils below
the fill.
• If the existing waterline is not rerouted, it is recommended that the alluvial soils
below the road fill be pressure -grouted to mitigate a risk for damage of the
' waterline. This pressure -grouting should be done prior to implementation of any
dewatering system on both sides of El Chimisal Road or any alluvial removals.
' If a dewatering system or pressure -grouting program is considered, additional
studies will be required to develop specific recommendations.
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Canyon Subdrains
Following cleanouts to competent bedrock or approved foundation materials, canyon
subdrains should be installed along the axes of all major canyons and tributary areas
where the depth of structural fill exceeds approximately 15 feet. Canyon subdrains
will mitigate potential build-up of hydrostatic pressures below compacted fills due to
infiltration of surface waters. Actual locations of the subdrains will have to be
determined during grading, including the most feasible exit points for discharge of
water. Typical construction details are shown on Plate SG -4 (Appendix Q.
DIsposaLoLQvmizeRock
Some oversize rock (rock greater than 12 inches in maximum dimension) is located
within the natural drainages along Redhawk Parkway and Nighthawk Pass. Oversize
rock may be disposed of onsite by placing it in the lower portions of the deeper fills
and in a manner to avoid nesting. The rock should be placed individually or in
windrows and then completely covered with finer -grained, onsite earth materials. The
finer -grained materials should be thoroughly watered and rolled to ensure closure of
all voids. A typical rock disposal detail is shown on Plate SG -2 (Appendix Q.
EHLPlacement
All fill should be placed in 6- to 8 -inch -thick maximum lifts, watered or air dried as
necessary to achieve near optimum moisture conditions and then compacted in place
to a minimum relative density of 90 percent. The laboratory maximum dry density and
optimum moisture content for each change in soil type should be determined in
accordance with Test Method ASTM D 1557-91.
Benching
Compacted fills placed against canyon walls and on natural slope surfaces inclining
at 5:1 (h:v) or greater should be placed on a series of level benches excavated into
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competent bedrock or dense native soils. Typical benching details are shown on
Plates SG -3, SG -4, SG -5, SG -7 and SG -8 (Appendix C).
Processing_ aMLLAreas
Where low-density surficial deposits of colluvium, alluvium or landslide debris, are
not removed in their entirety in cut areas (building pads and driveways), these
materials will require overexcavation to bedrock or competent native soils and
replacement as properly compacted fill.
rut/Fill Transition Lots
To minimize the detrimental effects of differential settlement, cut/fill transitions
should be eliminated from all building areas where the depth of fill placed within the
"fill" portion exceeds proposed footing depths. This should be accomplished by
overexcavating the "cut" portion and replacing the excavated materials as properly
compacted fill. Recommended depths of overexcavation are given below:
Depth of Fill
Depth of Overexcavation
Up to 3 feet
Equal depth
3 to 6 feet
3 feet
Greater than 6 feet
One-half the thickness of fill placed on
the "Fill' portion (15 feet maximum)
Horizontal limits of overexcavation should extend beyond perimeter building lines a
distance equal to the depth of overexcavation or to a minimum distance of 5 feet,
whichever is greater.
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Slap_e_Construction
Stability- almlations
Stability calculations were performed for the highest proposed 2:1 (h:v) cut (40 feet)
and fill (60 feet) slopes planned within the development. The calculations resulted in
factors of safety exceeding 1.5 and 1.1 for state and pseudo -dynamic (seismic) loading
conditions, respectively. Shear strength parameters presented in our 1989 report
(References) were used for calculations. A seismic coefficient of 0.29 was used for
seismic loading due to the proximity of the Elsinore fault. The calculations are
presented in Appendix D.
Cut_Slnpes
Cut slopes planned throughout the development are expected to be grossly stable to the
maximum planned height (40 feet) and at the maximum planned inclination of 2:1
(h:v). However, in -grading observation of individual cut slopes will be required by the
project engineering geologist to confirm favorable geologic structure of the exposed
bedrock. If highly fractured bedding, out -of -slope bedding, seepage or non-cemented
sand strata are observed, the cut slopes in question may require stabilization by means
of a compacted buttress fill or stabilization fill.
Ei1LSlopes
Fill slopes constructed with onsite earth materials will be grossly stable to the
maximum -planned height (60 feet) and at the maximum -planned inclination of
2:1 (h:v).
A fill key excavated a minimum depth of 2 feet into competent bedrock or dense native
soil will be required at the base of all fill slopes to be constructed on existing ground
surfaces sloping at a gradient of 5:1 (h:v) or greater. The width of the fill key should
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equal one-half the slope height or 15 feet, whichever is greater. Typical fill key
construction details are shown on Plates SG -3 and SG -7 (Appendix Q.
To obtain proper compaction to the face of fill slopes, low height fill slopes should be
overfilled and backfilled during construction and then trimmed back to the compacted
inner core. Where this procedure is not practical for higher slopes, final surface
compaction should be obtained by backrolling during construction to achieve proper
compaction to within 6 to 8 inches of the finish surface, followed by rolling with a
cable -lowered sheepsfoot and grid roller.
Fill AbQve_Cut_and-CuLw-Eill_Transitioi Slopes
'
Where fill -above -cut slopes are proposed, a 15 -foot -wide key excavated into
competent bedrock or dense native soil should be constructed along the contact. The
'
bottom of the key should be tilted back into the slope at a minimum gradient of two
percent. A typical section for construction of fill above cut slopes is shown on Plate
'
SG -7, (Appendix Q The lower cut portion of the slope should be excavated to grade
and observed by the project engineering geologist prior to constructing the fill portion.
Where cut to fill transition slopes are proposed, the fill portion should be placed on a
'
series of benches excavated into competent native soils or bedrock. The benches
should be at least 8 to 10 feet wide constructed at vertical intervals of approximately
5 feet and tilted back into the slope at a minimum gradient of two percent. Where cut -
to -fill transition contacts vary from about vertical to a few degrees from vertical,
'
benching of the fill portion into the cut portion, as recommended above, will be
difficult and may create a potential slip surface due to inadequate benching. Therefore,
'
partial overexcavation of the cut portion may be necessary to achieve adequate
benching and mitigate a potential slip surface.
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SIQRe i an apingand-MaultsIIance
Proper slope and pad drainage are essential in the design of grading for the subject
tract. An anticipated rainfall equivalency on the order of 60 to 100± inches per year
at the site can result due to irrigation. The overall stability of the graded slopes should
not be adversely affected provided all drainage provisions are properly constructed and
maintained thereafter and provided all engineered slopes are landscaped with a deep-
rooted, drought -tolerant and maintenance -free plant species, as recommended by the
project landscape architect. Additional comments and recommendations are presented
below with respect to slope drainage, landscaping and irrigation. A discussion of pad
drainage is given in the following section.
The most common type of slope failure in hillside areas is the surficial type and
usually involves the upper I to 6± feet. For any given gradient, these surficial slope
failures are generally caused by a wide variety of conditions, such as: 1) overwatering;
2) cyclic changes in moisture content and density of slope soils from both seasonal and
irrigation -induced wetting and drying; 3) soil expansiveness; 4) time lapse between
slope construction and slope planting; 5) type and spacing of plant materials used for
slope protection; 6) rainfall intensity; and/or 7) lack of proper maintenance program.
Based on this discussion, the following recommendations are presented to mitigate
potential surficial slope failures.
' Proper drainage provisions for engineered slopes should consist of concrete terrace
drains, downdrains and energy dissipators (where required) constructed in
accordance with the LA County Grading Code. Provisions should also be made for
construction of compacted earth berms along the tops of all engineered slopes.
' All permanent engineered slopes should be landscaped as soon as practical at the
completion of grading. As noted, the landscaping should consist of a deep-rooted,
drought -tolerant and maintenance -free plant species. If landscaping cannot be
' provided within a reasonable period of time, jute matting or equivalent or a spray -
on product designed to seal slope surfaces should be considered as a temporary
measure to inhibit surface erosion.
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Irrigation systems should be installed on the engineered slopes and a watering
program then implemented which maintains a uniform, near -optimum moisture
condition in the soils. Overwatering and subsequent saturation of the slope soils
should be avoided. On the other hand, allowing the soils to dry -out is also
detrimental to slope performance.
Irrigation systems should be constructed at the surface only. Construction of
sprinkler lines in trenches should not be allowed without prior approval from the
soils engineer and engineering geologist.
t During construction of terrace drains and downdrains, care must be taken to avoid
placement of loose soil on the slope surfaces.
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A permanent slope maintenance program should be initiated for major slopes not
maintained by individual homeowners. Proper slope maintenance must include the
care of drainage and erosion control provisions, rodent control and repair of leaking
or damaged irrigation systems.
Provided the above recommendations are followed with respect to slope drainage,
maintenance and landscaping, the potential for deep saturation of slope soils is
considered very low.
Homeowners should be advised of the potential problems that can develop when
drainage on the pads and slopes is altered in any way. Drainage can be altered due
to the placement of fill and construction of garden walls, retaining walls,
walkways, patios, swimming pool, spas and planters.
Landscaping_EorCut_and- iU-Slopes_and_S_urfuial-Erosion
To mitigate surficial erosion, all graded cut and fill slopes should be landscaped with
a deep-rooted plant material requiring minimal cultivation and irrigation water in order
to thrive. An irrigation system should be installed; however, overwatering and
subsequent saturation of slope surfaces should be avoided. Moreover, the irrigation
system should consist of very shallow or above -grade piping to avoid the need for deep
trenching within the slope surfaces.
All graded slopes should be landscaped as soon as practical after the completion of
rough grading (whenever water is available for irrigation). If permanent landscaping
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cannot be provided within a reasonable period of time, jute matting, plastic sheeting
or a spray -on product designed to seal slope surfaces should be considered as a
temporary measure to inhibit surfrcial erosion.
As a further measure to inhibit surfrcial erosion, the tops of all cut and fill slopes
should be protected from surface runoff by means of top -of -slope compacted earth
berms and/or concrete interceptor drains which collect and divert surface nrnoff to
adjacent streets or other appropriate disposal areas.
NAturaLSlop_es
Natural slopes located along the eastern portion of the site are considered grossly
stable. However, surface soils are prone to downslope soil creep and possible
mudflow under heavy saturated conditions. Therefore, natural slopes located below
daylight cut lots should be protected from surface runoff and subsequent saturation of
surface soil by means of top -of -slope compacted earth berms.
Settlement_Monitoring-Coni&erations
Settlement of proposed deep -fill areas (25f/ eet or, more) should be monitored by the
use of near -surface monuments. In addition within the deep -canyon area (130 feet of
fill), deep monuments should be installed at depths of 45 and 90 feet below proposed
grades. The deep monuments should be surveyed for lateral and vertical location prior
to placement of fill to establish the initial elevation and location. The deep monuments
should be surveyed for vertical location during grading for each 20 feet of fill placed.
Vertical surveys should continue following grading in accordance with the schedule
presented in the referenced reports. Fill materials placed within 3 feet of the
monuments should be compacted with hand -compaction equipment. The near -surface
monuments should be installed directly following grading and also surveyed vertically
in accordance with the following schedule. At the time of the initial survey, the near -
surface monuments should be located horizontally.
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The survey monuments should be monitored on a weekly basis for the first 3 weeks,
then once every 2 weeks for a total of 1 month. Subsequent readings should be taken
once a month for 6 months or whenever the settlement appears to stabilize.
Surveys should be based on two independent benchmarks approved by Petra. The two
benchmarks should be located in areas not anticipated to be influenced by proposed
work or other outside factors. The second benchmark should be used to confirm the
stability of the first benchmark by surveying it each time the monuments are surveyed.
Vertical movement should be measured to the nearest 0.005 foot. If the error in loop
closure exceeds 0.05 foot, the loop should be resurveyed.
Extreme care must be exercised by the contractor at the site to avoid disturbing
settlement monuments once installed. No heavy equipment should be permitted within
3 feet of the monuments. The locations of monuments should be clearly marked with
lath -and -ribbon "baskets".
At this time, approximately two deep monuments and 15 near -surface monuments are
anticipated. Specific locations and quantities should be based on exposed conditions
in the field during grading.
Shrinkage,Bttlking_and-Sub sidence
Volumetric changes in earth quantities will occur when excavated onsite soil and
bedrock materials are replaced as properly compacted fill. Following is an estimate
of shrinkage and bulking factors for the various geologic units present onsite. These
estimates are based on in-place densities of the various materials and on the estimated
average degree of relative compaction achieved during grading.
• Fill Shrinkage of 0 to 5%
• Alluvium ..................................... Shrinkage of 10 to 15%
• ColluviumShrinkage of 10 to 15%
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• Slide Debris '................................... Shrinkage of10to 15%
' • Bedrock (Pauba Formation) ....................... Shrinkage of 0 to 5%
' Subsidence from scarification and recompaction of exposed bottom surfaces in
removal areas will vary from negligible in bedrock areas to approximately 0. 15 foot
' in dense native soils.
The above estimates of shrinkage and subsidence are intended as an aid for project
planners in determining earthwork quantities. However, these estimates should be
' used with some caution since they are not absolute values. Contingencies should be
made for balancing earthwork quantities based on actual shrinkage and subsidence that
' will occur during grading.
G otechnicaWhser ations
' An observation of clearing operations, removal of unsuitable surficial materials, cut
' and fill slope construction and general grading procedures should be performed by the
project soils engineer and/or engineering geologist. Fills should not be placed without
' prior approval from the geotechnical consultants
The project soils engineer or his qualified representative should be present onsite
during all grading operations to verify proper placement and compaction of fill, as well
' as to verify compliance with the other recommendations presented herein.
Post-Grading—Considerations
' IZtilii�SLenches
' All utility trench backfill within street rights-of-way, utility easements, under
sidewalks, driveways and building floor slabs and within or in proximity to slopes
' should be compacted to a minimum relative density of 90 percent. Where onsite soils
are utilized as backfill, mechanical compaction will be required. Density testing, along
1
Where utility trenches are proposed parallel to any building footing (interior and/or
exterior trenches), the bottom of the trench should not be located within a 1:1 (h:v)
plane projected downward from the outside bottom edge of the adjacent footing.
L,otDrainage
Positive drainage devices, such as sloping sidewalks, graded swales and/or area drains
' should be provided around each building to collect and direct all water away from the
' structures. Neither rain nor excess irrigation water should be allowed to collect or
pond against building foundations. Roof gutters and downspouts may be required on
the sides of buildings where yard -drainage devices cannot be provided and/or where
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with probing, should be performed by the project soils engineer or his representative,
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to verify proper compaction.
For deep trenches with vertical walls, backfill should be placed in approximately I-
'
to 2 -foot -thick maximum lifts and then mechanically compacted with a hydra -hammer,
pneumatic tampers or similar equipment. For deep trenches with sloped walls, backfill
'
materials should be placed in approximately 8- to 12 -inch -thick maximum lifts and
'
then compacted by rolling with a sheepsfoot tamper or similar equipment.
As an alternative for shallow trenches where pipe may be damaged by mechanical
compaction equipment, such as under building floor slabs, imported clean sand having
a sand equivalent value of 30 or greater may be utilized and jetted or flooded into
place. No specific relative compaction will be required; however, inspection, probing
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and, if deemed necessary, testing should be performed.
To avoid point loads and subsequent distress to clay, cement or plastic pipe, imported
'
sand bedding should be placed at least l foot above all pipe in areas where excavated
trench materials contain significant cobbles. Sand bedding materials should be
'
thoroughly jetted prior to placement of backfill.
Where utility trenches are proposed parallel to any building footing (interior and/or
exterior trenches), the bottom of the trench should not be located within a 1:1 (h:v)
plane projected downward from the outside bottom edge of the adjacent footing.
L,otDrainage
Positive drainage devices, such as sloping sidewalks, graded swales and/or area drains
' should be provided around each building to collect and direct all water away from the
' structures. Neither rain nor excess irrigation water should be allowed to collect or
pond against building foundations. Roof gutters and downspouts may be required on
the sides of buildings where yard -drainage devices cannot be provided and/or where
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roof drainage is directed onto adjacent slopes. All drainage should be directed to
adjacent streets.
TentatiYeEoundatiQn.Designjzecommendations
FootingS_ethacks From Des—cmdingSlopes
Building setbacks from adjacent descending slopes should conform with Figure 18-I-1
of the 1994 UBC, Chapter 18, Division 1. The required setbacks are 1-1/3 (one-third the
slope height) measured along a horizontal line projected from the lower outside face
of the footing to the slope face. The footing setbacks should be 5 feet minimum where
the slope height is 15 feet or less and vary up to 40 feet maximum where the slope
height exceeds 15 feet. Deepened footings may be used to achieve the required
setbacks.
B_uikiing_Clearanc-es From Ascemding-SIo.Res
Building clearances from ascending slopes should also conform with Figure 18-I-1 of
the 1994 UBC. The required minimum building clearance is H/2 (one-half the slope
height) measured between the face of the building and the toe of the ascending slope.
The clearances will vary from 5 feet minimum for slopes up to 10 feet high to 15 feet
maximum for slopes exceeding a height of 10 feet. A retaining wall may be
constructed at the base of the slopes to achieve the required building clearances.
Altnwable Hearingl'alues
An allowable bearing value of 1,500 pounds per square foot is recommended for
design of 24 -inch -square pad footings and 12 -inch -wide continuous footings founded
at a minimum depth of 12 inches below the lowest adjacent final grade. This value
may be increased by 20 percent for each additional 1 foot of width or depth, to a
maximum value of 2,500 pounds per square foot. Recommended allowable bearing
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values include both dead and live loads and may be increased by one-third when
' designing for short -duration wind and seismic forces.
' Settlemen
Based on the expected general settlement characteristics of the different soil types that
will underlie the building sites and anticipated loading, it has been estimated that the
maximum total footing settlement will be approximately 0.75 inch and that differential
settlement will be about one-half the total settlement over a horizontal distance of 25
to 50t feet. It is expected that the majority of the footing settlements will occur during
' construction or shortly thereafter as building loads are applied.
' The above estimates are based on the assumption that the grading will be performed
in accordance with the grading recommendations presented elsewhere in this report
' and that the project geotechnical consultant will observe or test the soil conditions
exposed in the footing trenches.
In areas where saturated alluvial deposits exist below the groundwater level and are
tleft in-place below the proposed compacted fills, there may be a possibility that
settlement monitoring data will indicate that the effects of long-term settlement (of the
' alluvial soils) will result in settlements exceeding the above estimates. Therefore,
special foundation design recommendations, such as post -tensioned slabs or
strengthened foundations may become necessary on affected lots. This condition will
require evaluation when definitive settlement monitoring data are available.
Lateral Resistance
A passive earth pressure increasing at a rate of 250 pounds per square foot per foot of
depth, to a maximum value of 2,500 pounds per square foot, may be used to determine
lateral bearing resistance for footings. In addition, a coefficient of friction of 0.40
times the dead load forces may be used between concrete and the supporting soils to
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determine lateral sliding resistance. Lateral -bearing and lateral -sliding resistance may
be combined without reduction. In addition, an increase of one-third of the above
values may be used when designing for short -duration wind and seismic forces.
The above values are based on footings placed directly against compacted fill,
competent native soils or bedrock. In the case where footing sides are formed, all
backfill placed against the footings should be compacted to at least 90 percent of
maximum dry density.
Exp ansiYe-Soil_C onsid etations
Results of our laboratory tests indicate the majority of the onsite soil and bedrock
materials exhibit a VERY LOW expansion potential as classified in accordance with
Table 18 -I -B of the 1994 Uniform Building Code (UBC). However, laboratory test
data also indicate that local clay strata in the terrace deposits and Pauba bedrock
exhibit a HIGH expansion. On the basis of the test data, it is expected that the
foundation soils underlying a majority of the building sites will exhibit a VERY LOW
expansion potential while others will exhibit expansion potentials ranging from LOW
to HIGH. Consequently, expansive soil conditions will have to be evaluated on a lot
by lot basis during and at the completion of grading; however, tentative design
recommendations for footings and floor slabs for each of the above four possible soil
conditions are provided in the following sections for your consideration.
1. YeLy T,ow-Expansion_I'oteatial (Expansion Index of 0 to 20)
a. Footings
i. Exterior building footings may be founded at the minimum depths
indicated in UBC Table 18 -I -D (i.e. 12 -inch minimum depth for one-story
construction and 18 -inch -minimum depth for two-story construction).
Interior bearing -wall footings for both one- and two-story construction may
be founded at a minimum depth of 12 inches below the lowest adjacent
final grade. All continuous footings should be reinforced with a minimum
of two No. 4 bars, one top and one bottom.
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ii. Interior isolated -pad footings supporting raised -wood floors should be a
minimum of 24 inches square and founded at minimum depths of 12 and
18 inches below the lowest adjacent final grade for one- and two-story
construction, respectively. No special reinforcement of the pad footings
will be required.
iii. Exterior isolated -pad footings intended for support of roof overhangs, such
as second -story decks, patio covers and similar construction, should be a
minimum of 24 inches square and founded at a minimum depth of 18
inches below the lowest adjacent final grade. No special reinforcement of
the pad footings will be required.
b. Building-Ho_or__Slabs
' i. Living -area concrete floor slabs should be a nominal 4 inches thick and
reinforced with either 6 -inch by 6 -inch, No. 10 by No. 10 welded -wire
' mesh; or with No. 3 bars spaced a maximum of 24 inches on centers, both
ways. All slab reinforcement should be supported on concrete chairs or
brick to ensure the desired placement near mid -depth.
ii. Living -area concrete floors should be underlain with a moisture vapor
' barrier consisting of a polyvinyl chloride membrane, such as 6 -mil
Visqueen or equivalent. All laps within the membrane should be sealed
and at least 2 inches of clean sand should be placed over the membrane to
promote uniform curing of the concrete.
iii. Garage -floor slabs should be a nominal 4 inches thick and reinforced in a
' similar manner as living area floor slabs. Garage -floor slabs should also be
poured separately from adjacent wall footings with a positive separation
maintained with 3/e -inch -minimum felt expansion joint materials and
' quartered with weakened plane joints. A 12 -inch -wide grade beam founded
at the same depth as adjacent footings should be provided across garage
entrances. The grade beam should be reinforced with two No. 4 bars, one
top and one bottom.
iv. Presaturation of the subgrade soils below floor slabs will not be required;
' however, prior to placing concrete, the subgrade soils should be prewatered
to promote uniform curing of the concrete and minimize the development
of shrinkage cracks.
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2. Low .xpansinn Potential (Expansion Index of 21 to 50)
' a. Footings
i. Exterior building footings may be founded at the minimum depths
indicated in U.B.C. Table 18 -I -D (i.e. 12 -inch minimum depth for one-story
construction and 18 -inch -minimum depth for two-story construction).
' Interior bearing -wall footings for both one- and two-story construction may
be founded at a minimum depth of 12 inches below the lowest adjacent
final grade. All continuous footings should be reinforced with a minimum
' of two No. 4 bars, one top and one bottom.
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ii. Interior isolated -pad footings supporting raised -wood floors should be a
minimum of 24 inches square and founded at minimum depths of 12 and
18 inches below the lowest adjacent final grade for one- and two-story
construction, respectively. The pad footings should be reinforced with
No. 4 bars spaced a maximum of 18 inches on centers, both ways, near the
bottoms of the footings.
iii. Exterior isolated -pad footings intended for support of roof overhangs, such
as second -story decks, patio covers and similar construction, should be a
minimum of 24 inches square and founded at a minimum depth of 18
inches below the lowest adjacent final grade. The pad footings should be
reinforced with No. 4 bars spaced a maximum of 18 inches on centers, both
ways, near the bottoms of the footings.
b. Bui1ding_Elo_or_S1abs
i. Unless a more stringent design is recommended by the project architect or
structural engineer, we recommend a minimum slab thickness of 4 inches
for both living -area and garage -floor slabs and reinforcement consisting of
either 6 -inch by 6 -inch, No. 6 by No. 6 welded -wire mesh or No. 3 bars
spaced a maximum of 18 inches on centers, both ways. All slab
reinforcement should be supported on concrete chairs or brick to ensure the
desired placement near mid -depth.
ii. Living -area concrete floor slabs should be underlain with a moisture vapor
barrier consisting of a polyvinylchloride membrane such as 6 -mil Visqueen
or equivalent. All laps within the membrane should be sealed and at least
2 inches of clean sand should be placed over the membrane to promote
uniform curing of the concrete.
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iii. Garage -floor slabs should be poured separately from adjacent wall footings
with a positive separation maintained with 3/e -inch -minimum felt expansion
joint materials and quartered with weakened -plane joints. A 12 -inch -wide
grade beam founded at the same depth as adjacent footings should also be
provided across garage entrances. The grade beam should be reinforced
with two No. 4 bars, one top and one bottom.
iv. Prior to placing concrete, the subgrade soils below living -area and garage -
floor slabs should be prewatered to achieve a moisture content that is at
least equal to or slightly greater than optimum moisture content. This
moisture should penetrate to a depth of approximately 12 inches into the
subgrade.
3. Medium_Expansion Potential (Expansion Index of 51 to 90)
a. Eaatings
i. All exterior footings for both one- and two-story construction should be
founded at a minimum depth of 18 inches below the lowest adjacent final
grade. Interior footings may be founded at a minimum depth of 12 inches
below the lowest adjacent final grade. All continuous footings should be
reinforced with two No. 4 bars, one top and one bottom.
ii. Interior isolated -pad footings supporting raised floors should be a minimum
of 24 inches square and founded at a minimum depth of 18 inches below
the lowest adjacent final grade. The pad footings should be reinforced with
No. 4 bars spaced a maximum of 18 inches on centers, both ways, near the
bottoms of the footings.
iii. Exterior isolated -pad footings intended for support of roof overhangs, such
as second -story decks, patio covers and similar constriction, should be a
minimum of 24 inches square and founded at a minimum depth of 18
inches below the lowest adjacent final grade. The pad footings should be
reinforced with No. 4 bars spaced a maximum of 18 inches on centers, both
ways, near the bottoms of the footings.
b. RuildingXtoor Slabs
Unless a more stringent design is recommended by the architect or
structural engineer, we recommend a minimum slab thickness of 4 inches
for both living area and garage floor slabs and reinforcement consisting of
No. 3 bars spaced a maximum of 18 inches on centers, both ways. All slab
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reinforcement should be supported on concrete chairs or brick to ensure the
desired placement near mid depth.
[i. Living -area concrete floor slabs should be underlain with a moisture vapor
barrier consisting of a polyvinylchloride membrane such as 6 -mil visqueen
or equivalent. All laps within the membrane should be sealed and at least
2 inches of clean sand should be placed over the membrane to promote
uniform curing of the concrete.
iii. Garage -floor slabs should be poured separately from adjacent wall footings
with a positive separation maintained with 3/e -inch -minimum felt expansion
joint materials and quartered with weakened plane joints. A 12 -inch -wide
grade beam founded at the same depth as adjacent footings should also be
provided across garage entrances. The grade beam should be reinforced
with two No. 4 bars, one top and one bottom.
iv. Prior to placing concrete, the subgrade soils below all living -area and
garage -floor slabs should be presoaked to achieve a moisture content that
is 5 percent or greater above optimum moisture content. This moisture
content should penetrate to a minimum depth of 18 inches into the
subgrade.
4 Hig F.xpansinn Potential (Expansion Index of 91 to 130)
a. Eoatin;s
i. All exterior footings for both one- and two-story construction should be
founded at a minimum depth of 24 inches below the lowest adjacent final
grade. Interior footings may be founded at a minimum depth of 18 inches
below the lowest adjacent final grade. All continuous footings should be
reinforced with four No. 4 bars, two top and two bottom.
ii. Interior isolated -pad footings supporting raised floors should be a minimum
of 24 inches square and founded at a minimum depth of 24 inches below
the lowest adjacent final grade. The pad footings should be reinforced with
No. 4 bars spaced a maximum of 18 inches on centers, both ways, near the
bottoms of the footings.
iii. Exterior isolated pad footings intended for support of roof overhangs, such
as second story decks, patio covers and similar constriction, should be a
minimum of 24 inches square and founded at a minimum depth of 24
inches below the lowest adjacent final grade. The pad footings should be
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US HOME
TRs 23066-5 & 23067/Redhawk
May 6, 1998
J.N. 163-98
Page 30
reinforced with No. 4 bars spaced a maximum of 18 inches on centers, both
ways, near the bottoms of the footings.
b. BRildjn Flnor Slabs
Unless a more stringent design is recommended by the project architect or
structural engineer, we recommend a minimum slab thickness of 5 inches
for both living area and garage -floor slabs and reinforcement consisting of
No. 3 bars spaced a maximum of 18 inches on centers, both ways. All slab
reinforcement should be supported on concrete chairs or brick to ensure the
desired placement near mid depth.
Living -area concrete floor slabs should be underlain with a moisture vapor
barrier consisting of a polyvinylchloride membrane such as 6 -mil visqueen
or equivalent, placed on top of a 4 -inch -thick sand or gravel base. All laps
ld be
an
itional 2
swithin the and should be placed over the membrane and
o promote umhes of clean
concrete. wring of the
concrete.
iii. Garage floor slabs should be poured separately from adjacent wall footings
with a positive separation maintained with 3/s -inch -minimum felt expansion
joint materials and quartered with weakened plane joints. A 12 -inch -wide
by 24 -inch -deep grade beam should also be provided across garage
entrances. The grade beam should be reinforced with four No. 4 bars, two
top and two bottom.
iv. Prior to placing concrete, the subgrade soils below all living area and
garage -floor slabs should be presoaked to achieve a moisture content that
is 5 percent or greater above optimum moisture content. This moisture
content should penetrate to a minimum depth of 24 inches into the
subgrade.
Atterh-er9J units
The 1994 UBC specifies that slab -on -ground foundations (floor slabs) resting on soils
with an expansion index greater than 20 require special design considerations in
accordance with Section 1815. The design procedures outlined in Section are
based on the effective plasticity index of the different soil layers existing withithin the
upper 15 feet of the building site (i.e, subsurface stratigraphy and distribution of the
I
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US HOME
TRs 23066-5 & 23067/Redhawk
May 6, 1998
J.N. 163-98
Page 31
different soil types). Therefore, on lots where the foundation soils exhibit LOW,
MEDIUM or HIGH expansion potentials, effective plasticity indices will require
evaluation during and at the completion of grading. Depending on the results of these
evaluations, modification of the preceding recommendations may be necessary to
conform with UBC Section 1815.
Eaoting—OJ mati.aW
' All foundation excavations should be observed by a representative of the project
geotechnical consultant to verify that they have been excavated into competent bearing
soils or bedrock and to the minimum depths recommended herein. These observations
' should be performed prior to the placement of forms or reinforcement. The
excavations should be trimmed neat, level and square. All loose, sloughed or
moisture -softened soils and/or any construction debris should be removed prior to the
placement of concrete. Excavated soils derived from footing and utility trenches
' should not be placed in slab -on -grade areas unless they are compacted to at least 90
percent of maximum dry density.
SQlnhle.n ate—Cansidera6ons
' Laboratory test data indicate onsite soil and bedrock materials contain water-soluble
sulfate contents of less than 0.10 percent. Based on the test results, a NEGLIGIBLE
' exposure to sulfate can be expected for concrete placed in contact with onsite soils as
classified in UBC Table 19-A-3. Therefore, Type I or II cement or equivalent may be
' used for concrete exposed to the onsite soils or bedrock
' Foundation nesign-ParamdgTs
Retaining -wall footings may be designed using the allowable -bearing and lateral-
' resistance values recommended for design of residential footings; however, when
calculating passive resistance, the upper 6 inches of the footings should be ignored in
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US HOME
TRs 23066-5 & 23067/Redhawk
May 6, 1998
J.N. 163-98
Page 32
areas where the footings will not covered with concrete flatwork. Additionally, where
footings are constructed on or within 5 feet of the top(s) of the descending slope(s), the
passive earth pressure should be reduced to 150 pounds per square foot, per foot of
depth, to a maximum value of 1,500 pounds per square foot.
CmstrILCd tLOm-�nd
Footings for retaining walls proposed within the level areas of the property and at least
7 feet from the tops of the descending cut and fill slopes may be founded at a
minimum depth of 12 inches below the lowest adjacent final grade; however, a
minimum footing embedment of 18 inches may be preferable to allow for 6 inches of
soil cover over the footings.
C Mructio_n_On_()XAear_n scending-Slopes
Footings for retaining walls proposed on or near the tops of descending cut and fill
Slopes exceeding a height of 10 feet should be founded at a depth that will provide a
minimum footing setback of 7 feet measured along a horizontal line projected from the
outside bottom edges of the footings to the daylight contact with the slope face. This
footing setback may be reduced to 5 feet where the slope height is 10 feet or less.
Construction of footings at the above recommended minimum embedments is expected
to place the footings below any future creep -affected slope soils, as well as provide
sufficient vertical and lateral support for the footings without subjecting the footings
to detrimental settlement or jeopardizing the stability of the slope.
i ateral_Earth Pressures
Active earth pressures equivalent to a fluid having densities of 40 and 63 pounds per
cubic foot are tentatively recommended for design of cantilevered walls supporting a
level backfill and ascending 2:1 (h:v) backfill, respectively. For walls that are
restrained at the top, at -rest earth pressures equivalent to a fluid having densities of 60
and 95 pounds per cubic foot are recommended for design of restrained walls
US HOME
TRs 23066-5 & 23067/Redhawk
May 6, 1998
J.N. 163-98
Page 33
supporting a level backfill and ascending 2:1 (h:v) backfill, respectively. The above
values are for a well -drained backfill. All walls should also be designed to support any
adjacent structural surcharge loads imposed by other nearby walls or footings in
addition to the above active earth pressures.
Drainage
Perforated pipe and gravel subdrains should be installed behind the retaining walls to
prevent entrapment of water in the backfill. Perforated pipe should consist of 4 -inch -
minimum diameter PVC Schedule 40 or ABS SDR -35, with the perforations laid
down. The pipe should be encased in a 1 -foot -wide column of 0.75 inch to 1.5 -inch
open -graded gravel extending above the wall footing to a minimum height equal to
one-third the wall height or to a minimum height of 1.5 feet above the footing,
whichever is greater. The gravel should be completely wrapped in filter fabric
consisting of Mirafi 140N or equivalent. Solid outlet pipes should be connected to the
subdrains and then routed to a suitable area for discharge of accumulated water, such
as the proposed onsite area drainage system.
watetpmofmg
The portions of retaining walls supporting backfill should be coated with an approved
waterproofing compound or covered with a similar material to inhibit infiltration of
moisture through the walls.
Backfill
All wall backfill should be placed in approximately 8- to 12 -inch -thick maximum lifts,
watered or air-dried as necessary to achieve near optimum moisture conditions and
then mechanically compacted in place to a minimum relative compaction of 90
percent. Flooding or jetting of the backfill should be avoided. A representative of
Petra should probe and test the wall backfills to verify adequate compaction.
9
' US HOME May 6, 1998
TRs 23066-5 & 23067/Redhawk J.N. 163-98
Page 34
CmIer-de- atwnrk
On lots where foundation soils exhibit a Very Low or Low expansion potential,
' concrete sidewalks and patio -type slabs should be at least 3.5 inches thick and
provided with construction joints or expansion joints every 6 feet or less. Concrete
driveway slabs should be at least 4 inches thick and provided with construction joints
or expansion joints every 10 feet or less. On lots where the foundation soils exhibit a
Medium or High expansion potential, concrete sidewalks and patio -type slabs should
be at least 4 inches thick and concrete driveway slabs should be at least 5 inches thick.
To minimize cracking of concrete flatwork, the subgrade soils below concrete flatwork
areas should first be compacted to a minimum relative compaction of 90 percent and
then thoroughly wetted to achieve a moisture content that is at least equal to or slightly
greater than optimum moisture content. This moisture should penetrate to a depth of
12 inches into the subgrade and maintained in the soils during placement of concrete.
Prewatering of the soils will promote uniform curing of the concrete and minimize the
development of shrinkage cracks. A representative of the project geotechnical
consultant should observe and verify the density and moisture content of the soils and
the depth of moisture penetration prior to pouring concrete.
Mas onry-Block_Garden- aUs
Footings for masonry block walls may be founded at a depth of 12 inches below the
lowest adjacent final grade; however, where block walls are planned on or near the
tops of descending cut and fill slopes exceeding a height of 10 feet or natural slopes
regardless of height, the footings should be deepened to provide a minimum setback
of 7 feet between the outside bottom edges of the footings and the slope face. Where
cut and fill slopes are less than 10 feet high, the footing setbacks may be reduced to
5 feet. All footings should be reinforced with a minimum of two No. 4 bars, one top
and one bottom, to mitigate cracking related to the potential effects of differential
���30�10-s 7�o�3a�7
US HOME
TRs 23066-5 & 23067/Redhawk
May 6, 1998
J.N. 163-98
Page 35
settlement and/or expansion. Positive separations should also be provided in the walls
at horizontal intervals of approximately 20 to 25 feet and at each corner.
INV STT ATION LIMITATiO]yS
This report is based on the project as described and the geoteclmical data obtained
from the field tests performed at the locations indicated on the plan. The materials
encountered on the project site and utilized in our laboratory investigation are believed
O$ADIlY-GPi AN REYTFW ANIZ-
This report has been prepared for the exclusive use of US Homes to assist the project
and architect in the design of the proposed development. It is recommended
engineer
that Petra be engaged to review the final design drawings and specifications prior to
This is to verify that the recommendations contained in this report have
construction.
been properly interpreted and are incorporated into the project specifications. If Petra
is not accorded the opportunity to review these documents, we can take no
responsibility for misinterpretation of our recommendations.
We recommend that Petra be retained to provide soil engineering services during
construction of the excavation and foundation phases of the work. This is to observe
compliance with the design, specifications or recommendations and to allow design
changes in the event that subsurface conditions differ from those anticipated prior to
start of construction.
If the project plans change significantly (e.g., building loads or type of structures), we
should be retained to review our original design recommendations and their
applicability to the revised construction. If conditions are encountered during
construction that appear to be different than those indicated in this report, this office
should be notified immediately. Design and construction revisions may be required.
INV STT ATION LIMITATiO]yS
This report is based on the project as described and the geoteclmical data obtained
from the field tests performed at the locations indicated on the plan. The materials
encountered on the project site and utilized in our laboratory investigation are believed
US HOME
TRs 23066-5 & 23067/Redhawk
May 6, 1998
J.N. 163-98
Page 36
representative of the total area. However, soils can vary in characteristics between
excavations, both laterally and vertically.
The conclusions and opinions contained in this report are based on the results of the
described geotechnical evaluations and represent our best professional judgement. The
findings, conclusions and opinions contained in this report are to be considered
tentative only and subject to confirmation by the undersigned during the construction
process. Without this confirmation, this report is to be considered incomplete and
Petra or the undersigned professionals assume no responsibility for its use. In
addition, this report should be reviewed and updated after a period of one year of if the
site ownership or project concept changes from that described herein.
This report has not been prepared for use by parties or projects other than those named
or described above. It may not contain sufficient information for other parties or other
purposes.
The professional opinions contained herein have been derived in accordance with
current standards of practice and no warranty is expressed or implied.
Respectfully
CB/S
QRpFESSlp�
F
o,
w � .-•
41
ExV.
Sia froudi; PitD
Princi r?
RCE 36 F CAt%
tv
' Blake, T.F, 1996, "BQFAULT" - A Computer Program for the Deterministic
Prediction of Peak Horizontal Acceleration from Digitalized California
Faults.
H
Campbell, K.W. and Bozorgnia, Y., 1994, "Near -Source Attenuation of Peak-
Horizontal
eakHorizontal Acceleration from Worldwide Accelograms Recorded from 1957
to 1993"; Proceedings, Fifth U.S. National Conference on Earthquake
Engineering, Vol. III, Earthquake Engineering Institute, pp. 283-292.
International Conference of Building Officials, 1994, Uniform Building Code,
Structural Engineering Design Provisions, Volume 2.
Kennedy, Michael P., 1977, Recency and Character of Faulting along the Elsinore
Fault Zone in Southern Riverside County, California, Corridor Design
Management Group Special Report 131.
Petra Geotechnical, Inc., Supplemental Soils Engineering and Engineering Geologic
Investigation, Portion of Redhawk Project, Vesting of Tentative Tract Map
Nos. 23064, 23065, 23066 and 23067, Rancho California, County of
Riverside, California, J.N. 298-87, dated May 8, 1989.
1997, Supplemental Evaluation of Faulting, Southwest Portion ofRedhawk
Project, Rancho California Area, County of Riverside, California,
J.N. 298-87, dated March 1, 1989.
USGS, Pechanga Quadrangle, 7.5 Minute Topographic Series, 1968, photorevised
1988.
RiYerside-County_Flood Control AeriaLP.hotos
Date
Photo Number
Scale
1„
01/30/62
3-402
2,000
06/20/74
1041, 1042
2,000
11/27/83
203,204
1,600
04/10/90
19-23, 19-24
1,600
02/03/95
20-13/20-14, 19-18/19-19
1,600
' PETRA GEOTECHNICAL, INC.
J.N. 163-98 May 6, 1998
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LOGS OF BORINGS
1 AND TRENCHES
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1 PETRA GEOTECHNICAL, INC.
J.N. 163-98 May 6, 1998
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E X P L O R A T I O N L 0 G
Project: PROPOSED RESIDENTIAL DEVELOPMENT
Boring No.:B-1
Location:W of Intersection Redhawk Parkway/EI Chemisal Road
Elevation: 1215
lob No.: 163-98
Client: US HOMES
Date: 3/13/98
Drill Method: Hollowstem
Driving Weight: 140/30 in
Logged By: Steve W Jensen
Depth
(Feet)
ith-
logy
Material Description
W
a
a
r
Samples
Blows C B
Per r°
Foot e k
Laboratory Tests
oisture Dry Other
Content Density Lab
(Z) (Pcf) Tests
5
10
15
FTI I
@ 5.0 feet: SAND with Clay (SM): medium
brown, medium- to coarse-grained, moist, loose
AI Ll1S1I1IM
@ 15.0 feet: SAND with Clay (SM): medium
brown, medium- to coarse-grained, wet, loose
5/
7
4/
5
9.4
10.0
12.9
113.0
109.3
120.6
MAX
SO4
Continued Next Page
' Petra Geotechnical, Inc.
PLATE A-1
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E X P L O R A T I O N L 0 G
Project: PROPOSED RESIDENTIAL DEVELOPMENT
Boring No. :B-1
Location:W of Intersection Redhawk Parkway/EI Chemisal Road
Elevation: 1215
Job No.: 163-98
Client: US HOMES
Date: 3/13/98
Drill Method: Hollowstem
Driving Weight: 140/30 in
Logged By: Steve W Jensen
Depth
(Feet)
ith-
logy
Material Description
W
a
a
r
Samples
lows C B
Per 0
Foot e k
Laboratory Tests
Moisture Dry Other
Content Density Lab
(i) (pcf) Tests
—25—.@
30
35
@ 20.0 feet: Clayey SAND (SM/SC): medium
brown, wet
25.0 feet: No sample
@ 30.0 feet: No sample
@ 32.0 - 34.0 feet: cobble and gravel layer
1
5/
5
6/
6
32/
6"
16.3
14.2
114.7
125.5
CNSL
n11ATFDNAPV PAI IRA FORMATTnIJ
@ 35.0 feet: Poorly graded SAND (SP):
yellowish grey, coarse-grained, wet, dense
Continued Next Page
' Petra Geotechnical, Inc.
PLATE A-2
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E X P L O R A T I O N L 0 G
Project: PROPOSED RESIDENTIAL DEVELOPMENT
Boring No. :B-1
Location:W of Intersection Redhawk Parkway/EI Chemisal Road
Elevation: 1215
Job No.: 163-98
Client: US HOMES
Date: 3/13/98
Drill Method: Hollcwstem
Driving Weight: 140/30 in
Logged By: Steve W Jensen
Samples
Laboratory Tests
W
Material Description
loos C B
loisture Dry Other
Depth
Li
Per ° u
Content Density Lab
(Feet)
log
r
Foot e k
(Z) (pcf) Tests
@ 40.0 feet: Poorly graded SAND (SP):
50/
12.4
122.3
yellowish grey, coarse-grained, wet, dense
2"
TOTAL DEPTH OF BORING = 40'
GROUNDWATER ENCOUNTERED @ 25'
BORING BACKFILLED 03/13/98
Petra Geotechnical, Inc.
PLATE A-3
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E X P L O R A T I O N L 0 G
Project: PROPOSED RESIDENTIAL DEVELOPMENT
Boring No. :13-2
Location:W of Intersection Redhawk Parkway/EI Chemisal Road
Elevation: 1220
Job No.: 163-98
Client: US HOMES
Date: 3/12/98
Drill Method: Hollowstem
Driving Weight: 140/30 in
Logged By: Lisa Battiato
Depth
(Feet)
ith-
logy
Material Description
W
a
a
r
Samples
Laboratory Tests
lows
Per0
Foot
C
e
B
�
k
Moisture
Content
(i)
Ory
Density
(Pcf)
Other
Lab
Tests
5
—10—=
15
- _
_
=
=
- =
—
-
_ =
Z 77
= __
-_ -_
-
A' I lJIUM
@ 5.0 feet: Well -graded SAND (SW):
yellowish grey brown, fine- to coarse-grained,
wet, loose, no sample recovery
@ 10.0 feet: Well -graded SAND (SW): greyish
brown, fine- to coarse-grained, granitic, wet,
loose
@ 15.0 feet: Well -graded SAND (SW): greyish
brown, fine- to coarse-grained granitic, wet,
loose
1
1/
1
3/
6/
4
3/
3/
3
15.3
19.4
118.1
111.4
CNSL
Continued Next Page
Petra Geotechnical, Inc.
T,��,� 06 to - S, TA' a. 30 l0 7
PLATE A-4
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Project: PROPOSED RESIDENTIAL DEVELOPMENT
Boring No.:B-2
Location:W of Intersection Redhawk Parkway/EI Chemisal Road
Elevation: 1220
Job No.: 163-98 =
Client: US HOMES
Date: 3/12/98
Drill Method: Holloustem
Driving Weight: 140/30 in
Logged By: Lisa Battiato
Depth
(Feet)
ith-
logy
Material Description
W
alows
a
r
Samples
Laboratory Tests
Per
Foot
C
°
e
B
�
k
Moisture
Content
(i)
Dry
Density
(pcf)
Other
Lab
Tests
25
QUATERNARY PAUBA SANDSTONE
Poorly graded SAND (SP): yellow grey,
coarse-grained, wet, dense
To poorly graded, fine-grained SAND, yellow
brown, micaceous, wet, very dense
15/
3/60
5"
53/
g
17.5
116.0
d25.0
@ feet: Well -graded and Silty SAND:
yellowish brown, interlayered, fine- to
coarse-grained,micaceous, wet, dense
TOTAL DEPTH OF BORING = 25' 6"
GROUNDWATER ENCOUNTERED @ 4'
BORING BACKFILLED 03/12/98
Petra Geotechnical, Inc.
PLATE A-5
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E X P L O R A T I O N L 0 G
Project: PROPOSED RESIDENTIAL DEVELOPMENT
Boring No. :B-3
Location:W of Intersection Redhawk Parkway/EI Chemisal Road
Elevation: 1235
Job No.: 163-98
Client: US HOMES
Date: 3/12/98
Drill Method: Hollowstem
Driving Weight: 140/30 in
Logged By: Lisa Battiato
Depth
(Feet)
-it
log
Material Description
W
aloos
a
r
Samples
Laboratory Tests
Per
Foot
C
°
e
B
k
Moisture
Content
(i)
Dry
Density
(Pcf)
Other
Lab
Tests
5
10
15
/
/
FTI 1
Clayey SAND (SC): yellowish brown, fine- to
coarse-grained, moist, blocky
@ 3.5 feet: drilling becomes difficult, hit
meta andesite clast
@ 5.0 feet: Clayey SAND (SC): red, black
and yellow brown, mottled, with small granitic
and metavolcanic gravel, fine- to
coarse-grained, moist, dense
17/
54
14/
22/
27
18/
37/
32
8.5
7.8
8.3
123.8
116.9
126.0
CNSL
CNSL
@ 8.0 feet: Cobble layer: large tonalite
quartzite (sugary) fragments in cuttings,
fairly fresh, some iron oxide and manganese on
surfaces
@ 10.0 feet: Slightly clayey poorly graded
SAND (SP): predominately coarse-grained,
moist, well indurated, dense, contains sparse
1 -inch gravel
Af
@ 15.0 feet: Poorly graded SAND and Silty
SAND (SP): orange to dark grey brown,
horizontally layered, horizontal parting
surfaces, damp, very dense, sample disturbed
due to excessive blows
OI [ATFRNARY PAI IRA SANDSTONE
Continued Next Page
' Petra Geotechnical, Inc.
PLATE A-6
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E X P L O R A T I O N L 0 G
Project: PROPOSED RESIDENTIAL DEVELOPMENT
Boring No. :B-3
Location:W of Intersection Redhawk Parkway/EI Chemisal Road
Elevation: 1235
Job No.: 163-98
Client: US HOMES
Date: 3/12/98
Drill Method: Hollowstem
Driving Weight: 140/30 in
Logged By: Lisa Battiato
W
Samples
Laboratory Tests
low
Per°
Footle
C
B
u
k
Moisture
Content
(Z)
Dry
Density
(pcf)
Other
Lab
Tests
Depth
(Feet)
ith-
logy
Material Description
a
a
r
@ 20.0 feet: Clayey poorly graded SAND (SP):
7/
6.7
95.4
orange, very dark brown and yellow, mottled,
10/
coarse-grained, moist, dense, appears to have
22
soil development
TOTAL DEPTH OF BORING = 21' 6"
NO GROUNDWATER ENCOUNTERED
BORING BACKFILLED 03/12/98
Petra Geotechnical, Inc.
PLATE A-7
11
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E X P L O R A T I O N L 0 G
Project: PROPOSED RESIDENTIAL DEVELOPMENT
Boring No. :B-4
Location:W of Intersection Redhawk Parkuay/EI Chemisal Road
Elevation: 1228
Job No.: 163-98
Client: US HOMES
Date: 3/12/98
Drill Method: Hollowstem
Driving Weight: 140/30 in
Logged By: Lisa Battiato
Depth
(Feet)
ith-
las
Material Description
W
a
a
r
Samples
Laboratory Tests
lows
Per
Foot
C
°
e
B
u
k
Moisture
Content
(i)
Dry
Density
(pcf)
Other
Lab
Tests
5
10
15
A'I U11 IM Silty SAND (SM): grey brown, fine -
to coarse-grained, moist, loose to
medium dense
@ 5.0 feet: Silty SAND (SM): grey/brown, fine-
to coarse-grained (predominately
medium -grained), moist, medium dense, micaceous,
slightly blocky
@ 10.0 feet: Silty SAND (SM): grey brown,
fine- to coarse-grained, very moist to wet,
medium, dense, micaceous, moderate porosity
@ 13.0 feet: Cobble layer
@ 15.0 feet: Silty SAND (SM): orange, slightly
clayey, moist, fine- to coarse-grained, greyish
clay -lined parting surfaces or infilling of
desiccation cracks
7/
14/
19
9/
9
17/
40
3.8
12.9
14.5
108.0
118.3
117.8
Continued Next Page
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PLATE A-8
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E X P L O R A T I O N L 0 G
Project: PROPOSED RESIDENTIAL DEVELOPMENT
Boring No.:B-4
Location:W of Intersection Redhawk Parkway/EI Chemisal Road
Elevation: 1228
Job No.: 163-98
Client: US HOMES
Date: 3/12/98
Drill Method: Hollowstem
Driving Weight: 140/30 in
Logged By: Lisa Battiato
Depth
(Feet)
L ith-a
logy
Material Description
W
a
r
Samples
I Laboratory Tests
lows
Per
Foot
C B
r° j
e k
Moisture
Content
(Z)
Dry
Density
(pcf)
Other
Lab
Tests
25
Silty SAND (SM): yellow, fine- to
coarse-grained (predominately fine-grained),
moist, slightly clayey, very dense
35/
50/
4"
24/
50/
4"
11.4
11.8
122.2
114.5
_ -
@ 25.0 feet; Well -graded SAND (SW): yellowish
tan, fine- to coarse-grained, wet, very dense
TOTAL DEPTH OF BORING = 25' 10"
NO GROUNDWATER ENCOUNTERED
BORING BACKFILLED 03/12/98
Petra Geotechnical, Inc.
PLATE A-9
I
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CJ
I_���•�:��ifiti,��iizh
Project: PROPOSED RESIDENTIAL DEVELOPMENT
Boring No.:8-5
Location:W of Intersection Redhawk Parkway/EI Chemisal Road
Elevation: 1225
Job No.: 163-98
Client: US HOMES
Date: 3/12/98
Drill Method: Hollowstem
Driving Weight: 140/30 in
Logged By: Lisa Battiato
Depth
(Feet)
ith-
logy
Material Description
W
r
Samples
Laboratory Tests
lows
Per
Foot
C
°
e
B
k
Moisture
Content
(i)
Dry
Density
(Pcf)
Other
Lab
Tests
5
10
15
_- -_
- _
- =
- _
s =
_ -
-
—
_ =
=
ALLUUIUp
Well -graded SAND (SW): yellow brown, fine-
to coarse-grained, moist, loose
@ 4.5 feet: dark brown soil layer
@ 5.0 feet: Well -graded SAND (SW): brown,
fine- to coarse-grained, very moist, medium
dense
@ 10.0 feet: Well -graded SAND (SW): brown,
interlayered very coarse-grained and
coarse-grained units, wet, loose, the
coarse-grained unit was porous, no recovery
11/
12
6/
4
8.4
107.7
@ 15.0 feet: Poorly graded SAND (SP):
medium- to coarse-grained
Continued Next Page
Petra Geotechnical, Inc.
PLATE A-10
I
L
E X P L O R A T I O N L 0 G
Project: PROPOSED RESIDENTIAL DEVELOPMENT
Boring No.:5-5
Location:W of Intersection Redhawk Parkway/EI Chemisal Road
Elevation: 1225
Job No.: 163-98
Client: US HOMES
Date: 3/12/96
Drill Method: Hollowstem
Driving Weight: 140/30 in
Logged By: Lisa Battiato
Depth
(Feet)
ith-
logy
Material Description
W
a
a
r
Samples
lows C B
Per or l
Foot e k
Laboratory Tests
Moisture Dry Other
Content Density Lab
(7.) (pcf) Tests
—25-
525'
@ 20.0 feet: Poorly graded SAND (SP): tan,
coarse-grained, wet, micaceous
25'6": Boring terminated due to equipment
difficulties
TOTAL DEPTH OF BORING = 25' 6"
GROUNDWATER ENCOUNTERED @ 10.0'
BORING BACKFILLED 03/12/98
Petra Geotechnical, Inc.
PLATE A-11
I
' US HOMES May 6, 1998
' Redhawk/TRs 23066-5 & 23067 J.N. 163-98
Page A-1
'
Total Depth = 6.0 feet
LOG OF TEST PITS
No Groundwater Encountered
Test Pit
Trench Backfilled
Numb—r Depth
Description
T-2 0.0 - 1.0' Colluvium
Cla}e_y SANn (S): dark brown, fine- and coarse-
T-1 0.0-2.0'
COT.TAWTTiM
'
1.0 - 5.5' Bedrock: Pauha Formation
Clayey SAND (SQ: dark brown, fine- and coarse-
Silty SAND (SM): tan, fine- and coarse-grained
grained, very moist, loose, porous
'
2.0 - 3.5'
BEDROCK- PATTRA SANDSTONE.
Silty SAND (S): tan, fine- and coarse-grained
5.5 - 6.0' Silty SAND (S): orange and tan, fine- to medium -
(predominately coarse-grained), slightly moist, dense
'
dense
B: 44 39°SE
N44E
Total Depth = 6 feet
'
Groundwater @ 5 feet
3.5 - 5.5'
Silty SAND (,SM1: tan, predominately fine-grained, with
'
'
iron oxide staining, damp, dense
5.0 - 6.0'
Poorly graded SAND (SPI: orange, coarse-grained,
'
moist, dense
7,_2o?3alaz(7-.s, 77_1ea3Glo%
Total Depth = 6.0 feet
No Groundwater Encountered
Trench Backfilled
t
T-2 0.0 - 1.0' Colluvium
Cla}e_y SANn (S): dark brown, fine- and coarse-
grained, very moist, porous, rootlets, loose
'
1.0 - 5.5' Bedrock: Pauha Formation
Silty SAND (SM): tan, fine- and coarse-grained
(predominately coarse-grained), very moist, dense
'
5.5 - 6.0' Silty SAND (S): orange and tan, fine- to medium -
grained, interbedded with tan silty Sand, very moist,
'
dense
Total Depth = 6 feet
'
Groundwater @ 5 feet
Trench Backfilled
Trench located 4 feet from drainage due to standing
'
water in drainage.
7,_2o?3alaz(7-.s, 77_1ea3Glo%
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US HOMES May 6, 1998
RedhawWTRs 23066-5 & 23067 J.N. 163-98
Page A-2
Test Pit
Number Depth Description
T-3 0.0 - 1.0' Colluvium
Silty SAND (SM): very dark brown to black, very moist
to wet, semi -rounded granitic cobbles to 6 inches in
diameter, fine- to coarse-grained, roots, porous, loose
1.0- 2.0' Clayey SAND (,SQ: red, fine- to coarse-grained, slightly
porous, rootlets, very moist, medium dense
2.0 - 3.5' Bedrock- Pauba Formation
Silty SAND (SM): yellowish tan, fine- to coarse-grained,
moist, dense, clayey, seepage at 2.5 feet, caliche layers
parallel to slope at 3 feet, somewhat cemented, slightly
porous
3.5 - 6.0' Silty SAND (SMI: orange, fine- to coarse-grained, moist,
dense
Total Depth = 6 feet
Groundwater Seepage @ 2.5 feet
Trench Backfilled
T-4 0.0 - 5.0' Colluvium
Silty SAND (SM): very dark brown to black, fine- to
coarse-grained, loose, porous, wet, roots
5.0 - 11.0' Bedrosk:_Pauha Formation
Silty SAND (SM): yellow tan, fine- to coarse-grained,
very moist to wet, porous, some iron oxidation staining,
medium dense to dense
11.0 - 11.5' Well -graded SAND (SWI: yellow tan, micaceous, fine -
to coarse-grained, very moist, dense
No in -trench logging due to groundwater and caving
Total Depth = 11.5 feet
Groundwater @ 3.5 feet
Trench Backfilled
T-5 0.0 - 1.5' Colluvium
Silty SAND (SM): dark brown, fine- to coarse-grained,
very moist, loose, porous, roots
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US HOMES
RedhawkPTRs 23066-5 & 23067
Test Pit
May 6, 1998
J.N. 163-98
Page A-3
Number Depth Description
1.5 - 6.0' Bedrock: Pauba Formation
Interbedded Poorly graded SA (,Sp): orange, coarse-
grained, wet, friable, dense; and
SILT (ML : yellowish tan, fine-grained, micaceous,
manganese -stained, iron oxidation, desiccation surfaces,
firm, wet
Total Depth = 6.0 feet
Groundwater Seepage @ 4 feet
Trench Backfilled
T-6 0.0-8.01, Silty_SAhM (SM): dark brown, fine to coarse-grained,
porous, very moist, loose, rootlets
8.0" - 2.0' Colluvium
Clayey SAND O: red, fine- to coarse-grained, very
moist, medium dense, rootlets
2.0'- 6.0' Bedrock: Pauba Formation
Silty SAND (SM): yellowish tan, fine- to coarse-grained
with occasional semi -rounded granitic cobble 2 to 8
inches diameter, caliche stringers and layer at 2.0 feet; 6 -
inch cobble layer beneath caliche; roots throughout
resulting in secondary porosity, moist dense
Total Depth = 6.0 feet
No Groundwater
Trench Backfilled
T-7 0.0 - 2.0' Colluvium
Silty SAND (SM): dark brown, fine- to coarse-grained,
slightly clayey, rots, loose, porous, very moist
2.0 - 6.0' Bedrock' Pauba Formation
InterbeddedPoorlv graded SAND (SP_): orange, coarse-
grained, very moist to wet, iron oxidation horizons, roots,
friable, dense; and
SILT (MT l: yellowish grey, fine-grained, moist to wet,
roots desiccation surfaces, firm, micaceous
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US HOMES
Redhawk/TRs 23066-5 & 23067
Test Pit
iNumU_er
Total Depth = 6 feet
Groundwater Seepage @ 5 feet
Trench Backfilled
May 6, 1998
J.N. 163-98
Page A-4
T-8 0.0 - 7.5' Colluvium
Silty SAND (SM): dark brown to orangish brown,
slightly clayey, very moist to wet, porous, loose to dense
(density increasing with depth), roots, clayey from 6.5 to
7.5 feet
7.5 - 8.5' Bedrock• Pauba Formation
Silty SAND (SM): orangish brown, fine- to coarse-
grained, very moist, dense, manganese staining, slightly
porous
Total Depth = 8.5 feet
Groundwater Seepage @ 4 feet
Trench Backfilled
Significant Caving
T-9 0.0 - 8.0" C olluvi rn
Silty SAND (S): medium brown, fine- to coarse-
grained, wet, roots, porous, loose
8.011- 1.0' Clayey SAND (SQ: orange, fine- to coarse-grained, very
moist, medium dense, roots
1.0 - 3.0' Bedrock: PaubaEcirmatiQn
Well -.graded SAND (SW): orangish tan, fine- to coarse-
grained (predominately coarse-grained), very moist,
friable, medium dense
3.0 - 6.0' Poorly - ded SAND (,): orange, very coarse-grained,
very moist, friable, dense, occasional 1 inch gravel
Total Depth = 6 feet
No Groundwater Encountered
Trench Backfilled
T-10 0.0 - 1.0' Collum
Well -graded SAND (SW) with some Silt: very dark
greyish brown, wet, predominately coarse-grained,
rootlets, few gravel, loose
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US HOMES
Redhawk/TRs 23066-5 & 23067
Test Pit
May 6, 1998
J.N. 163-98
Page A-5
Number D Ah Descrip-tion
1.0 - 4.0' Clayey SAND (SQ: dark brown (reddish), fine- and
coarse-grained, moist with caliche stringers and
desiccation surfaces, rootlets, loose in upper 1 foot
4.0 - 5.0' Bedrock: Pauha Formation
Poorly graded SAND brown, predominate coarse-
grained, damp, dense
5.0 - 7.0' SAND (.';P): yellow, fine-grained, damp, medium dense
to dense
7.0 - 8.0' CLAY (Cl.):)a light grey brown, very firm, damp
Total Depth = 8.0 feet
No Groundwater Encountered
Trench Backfilled
T-11 0.0 - 1.0' CDHUYium
Sim SAND (SM): dark brown topsoil, well -graded sand
with silt, very moist, loose
1.0 - 4.0' Clayey SAND (SQ: reddish brown, wet, with semi -
rounded granitic cobbles to 12 inches diameter, firm
4.0 - 5.0' Bedrock• Pauha Formation
SILT (ML): yellow, fine-grained, moist, dense
Total Depth = 5.0 feet
Groundwater Seepage @ 3.0 feet
Trench Backfilled
Caving
T-12 0.0 - 1.0' Colluvium
Sim SAND (S): dark brown, fine- to coarse-grained,
moist, loose
1.0 - 5.0' Clayey SAND (SC): reddish brown, fine- and coarse-
grained, upper 1 foot is loose, dense, caliche stringers
and desiccation surfaces
5.0 - 6.0' Bedrock: Pauba Formation
SILT (MQ: yellow, moist, dense, friable
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US HOMES May 6, 1998
Redhawk/TRs 23066-5 & 23067 J.N. 163-98
Page A-6
Test Pit
N-umher Depth Description
Total Depth = 6.0 feet
No Groundwater Encountered
Trench Backfilled
Colluvium
T-13 1.0 - 2.0' Silty SAND (SM): dark brown, moist, with roots, loose
2.0 - 5.0' Bedrock: Pauba Formation
Poorly p adaded SAND (SPI: coarse-grained, moist,
medium dense, friable, indurated
Total Depth = 5.0 feet
No Groundwater Encountered
Trench Backfill
T-14 0.0 - 2.0' Coll�im
Silty.SAND (SMI: dark brown, fine- to coarse-grained,
very moist to wet, loose; seepage at 2 feet topsoil caving
into trench
2.0 - 5.0' CLAY (CQ: reddish brown, very firm, with caliche
stringers, digging very hard
5.0 - 6.5' Brock-Pauba Formation
Claxey SAND (SCS: reddish brown, fine- and coarse-
grained, moist, dense, very hard digging
6.5 - 7.0' Bedrock:_ Pauba Formation
Poorly graded SAND (S): reddish, fine- to coarse-
grained, moist, dense
Total Depth = 7.0 feet
Groundwater Seepage @ 2.0 feet
Trench Backfilled
T-15 0.0 - 2.0' Colluvium
Silty SAND (SMI: dark brown, fine- to coarse-grained,
moist, loose
2.0 - 4.0' Clayey SAND (SCI: reddish brown, fine- to coarse-
grained, wet, medium dense
4.0 - 6.0' Bedrock- Pauba Formation
Poorly graded SAND (,SP): orange, friable, dense,
nonindurated
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US HOMES
Redhawk/TRs 23066-5 & 23067
May 6, 1998
J.N. 163-98
Page A-7
Test Pit
Number Depth Description
Total Depth = 6.0 feet
Groundwater Seepage @ 2.0 feet
Trench Backfilled
T-16 0.0 - 2.0' Colluvium
Silty SAND (,SM): dark brown, fine-grained, moist, loose
2.0 - 5.0' Clayey SAND (SSI: orange -brown, fine- and coarse-
grained, very moist, medium dense, manganese staining
5.0 - 7.0' Bedrock- Pauhs Formation
Poorly graded SAND SPI: orange -brown, coarse-
grained, moist, dense
Total Depth = 7.0 feet
Groundwater Seepage @ 3.0 feet
Trench Backfilled
T-17 0.0 - 2.5' Alluvium_
Well -graded SAND (SWI: tan, fine- to coarse-grained,
moist, loose
2.5 - 3.0' Well -graded SAND (SW) with -some _Silt: dark brown,
fine- to coarse-grained, wet, loose
Total Depth = 3.0 feet
Groundwater Seepage @ 2.0 feet
Trench Backfilled
Excessive caving
T-18 0.0 - 6.0' Colluvium
Well -graded SiltT,SAND (,SW/SMI: topsoil, dark brown,
fine- to coarse-grained, moist, loose, organic odor
6.0 - 9.0' Clayey SAND (SC): orangish brown, fine- and coarse-
grained, moist, loose to medium dense
9.0 - 11.0' Weathered Bedrock: Pauba FormatiQu
Poorly ggraded SAND (S): orange, clayey, very moist,
wet, dense
Total Depth = 11.0 feet
No Groundwater Encountered
Trench Backfilled
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US HOMES
Redhawk/TRs 23066-5 & 23067
Test Pit
May 6, 1998
J.N. 163-98
Page A-8
Number Depth Description
T-19 0.0 - 1.0' Colluvium
Well -graded SAND (SW) with some Silt: dark brown,
moist, loose
1.0 - 5.0' Bedrock- Pauha Formation
Poor ygraded SAND (SP) with -some. -Clay: fine- and
coarse-grained, moist, dense
Total Depth = 5.0 feet
No Groundwater Encountered
Trench Backfilled
T-20 0.0 - 2.0' Alluvium
Wel]-graded SAND (SW): tan, thinly horizontally
bedded, moist, loose, caving
2.0 - 3.5' Well- graded SAND (SW/SM)_.w_ith some Silt: dark
brown, with dry grass rootlets, moist, loose to medium
dense
3.5 - 4.5' Clayey well -g> aded SAND (4W/SC): orangish brown,
fine- to coarse-grained, very moist, loose to medium
dense
4.5 - 6.0' Bedrock: Pauha Formation
Poorly_graded SAND (Sp): orange brown, predominately
coarse-grained, wet, nonindurated, medium dense
Total Depth = 6.0 feet
No Groundwater Encountered
Trench Backfilled
T-21 0.0 - 2.5' Colluvium
Well -graded SAND (SW/SM) with Silt: dark brown
topsoil, fine- to coarse-grained, moist, loose
2.5 - 5.0' Clavey4ANl (SC): orange -brown, fine- and coarse-
grained, very moist, medium dense
5.0 - 6.0' 1%drock Pauba Formation
Poorly graded SAND (S): orange -tan, predominately
coarse-grained, moist, dense
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US HOMES May 6, 1998
Redhawk/TRs 23066-5 & 23067 J.N. 163-98
Page A-9
Test Pit
NYumher Dep-th Description
Total Depth = 6.0 feet
No Groundwater Encountered
Trench Backfilled
T-22 0.0 - 1.0' FILL
Clayey SAND (,SQ: yellow/tan, fine- to coarse-grained
with chunks of concrete and asphalt, loose
1.0 - 3.5' Colluvium
Slightly gilts, We11-o-rqdad SAND (4W/SM): dark
brown, fine- to coarse-grained, very moist, loose
3.5 - 5.5' Slightly Cave- Silty SAND (SM/SCI: orange -brown,
fine- to coarse-grained, wet, medium dense, blocky
5.5 - 7.0' Bedrock: Pauba Formation
Poorly graded SAND withlayers of Clayey SAND
(SP/SCI: poorly graded Sand is orange brown,
predominately coarse-grained, moist, friable, dense;
clayey Sand is greyish brown, fine- to coarse-grained,
blocky with caliche and rootlets, very firm
Total Depth = 7.0 feet
No Groundwater Encountered
Trench Backfilled
T-23 0.0 - 10.0' Alluvium
Well-eraded SAN2(.S Wl: brown, fine- to coarse-grained
with few rounded granitic cobbles, very wet at 3 feet,
significant caving, loose
@ 9.0' Cobble layer, becoming more dense
Total Depth= 10.0 feet
Groundwater Seepage @ 4.0 feet
Trench Backfilled
T-24 0.0-9.01 Alluvium
bell-araded SAND (S_W): brown, fine- to coarse-
grained, loose, moist, thinly layered
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US HOMES May 6, 1998
Redhawk/TRs 23066-5 & 23067 J.N. 163-98
Page A-10
Test Pit
Numb -ex Depth Description
Total Depth = 9.0 feet
Groundwater Seepage @ 5.0 feet
Trench Backfilled
T-25 0.0 - 2.0' Colluvium
Slightly Clayey well -graded SAND (SW): very dark
brown, fine- and coarse-grained, wet, loose
2.0 - 3.0' (Clayey SAND (SP: yellowish grey brown, fine- and
coarse-grained, very moist, medium dense, slightly
blocky
3.0 - 5.0' Waath .eyed Bedrock: Pauba Formation
Slightly Clayey poorly graded SAND (ISR); yellowish
grey brown, fine- and coarse-grained, very moist,
medium dense
5.0 - 7.0' Poorly graded SAND (SPI: coarse-grained, friable, well -
indurated, moist, dense
Total Depth = 7.0 feet
Groundwater Seepage @ 5.0 feet
Trench Backfilled
T-26 0.0 - 1.0' C_olhLvium
f'laye-y_noody graded SAND (SP): brown, fine- and
coarse-grained, some 4 -inch cobbles, very moist, loose to
medium dense
1.0 - 3.0' Clayey SAND (SCQ: orange, moist, moderately dense,
blocky
3.0 - 8.0' Bedrock: Pauba Formation
Poorly, waded SAND (SPI: yellowish grey brown,
predominately coarse-grained, moist, dense
Total Depth = 8.0 feet
No Groundwater Encountered
Trench Backfilled
T-27 0.0 - 3.0' Colluvium
Clayey SAND (,SQ: brown, fine- and coarse-grained,
some 4- to 5 -inch cobbles, moist, some fine roots, loose
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US HOMES
Redhawk/TRs 23066-5 & 23067
Test Pit
May 6, 1998
J.N. 163-98
Page A-11
Number Depth Description
3.0 - 7.5' Clayey SANT) (SQ: moist, blocky, 4 -inch cobbles,
loose, occasional 12 -inch rocks
7.5 - 9.6' Bedrock: Pauha Formation
Poorly graded SANT) (SPI: yellowish grey brown, some
clay, medium -grained, moist
Total Depth = 9.6 feet
No Groundwater Encountered
Trench Backfilled
T-28 0.0 - 2.0' Colluvium
Silty SANT) (SM): brown, fine roots to 2 feet, some
gravel 2t inches, moist, loose
2.0 - 4.0'Clay_ev,-well_gcaded SANT) (S)LI: brown, moist, loose to
medium dense, blocky
4.0 - 8.0' Bedrock: Pauha Formation
Poorly graded __.SAND (SPS: yellowish grey brown,
coarse-grained, moderate porosity, moist, dense
Total Depth = 8.0 feet
No Groundwater Encountered
Trench Backfilled
T-29 0.0 - 3.5' Colluvium
Poorlyvaded SAND (SPI: brown, moist to wet, loose,
some 2 -inch gravel
3.5 - 4.0' Bedrock: Pauha Formation
SILT (MI ): light brown, fine-grained, well -indurated,
slightly damp, dense
4.0 - 7.5' SIL -T - (ML ): orange brown, fine-grained, well -indurated,
slightly damp, very dense
Total Depth = 7.5 feet
Groundwater Table n 4.0 feet
Trench Backfilled
T-30 0.0 - 1.0' Collum
Well aded SANT) (S-Mo—with-some-Silt: brown, moist,
loose
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US HOMES May 6, 1998
Redhawk/TRs 23066-5 & 23067 J.N. 163-98
Page A-12
Test Pit
Numher Depth Description
1.0 - 3.0' Clayey Poorly graded SAND (,qP-): orange brown,
medium -grained, fairly loose, moist
3.0 - 7.0' Bedrock: Pauba Formation
Poorly gradedSAND (SPI: orange grey brown, medium -
grained, moist, dense
Total Depth = 7.0 feet
No Groundwater Encountered
Trench Backfilled
T-31 0.0 - 1.0' Colluvium
Poorly graded SAND (SPI: brown, loose, very moist
1.0 - 4.5' Bedrock: Pauba Formation
Poorly grntied SAND (SB): orange brown, medium -
grained, moist, dense
Total Depth = 4.5 feet
No Groundwater Encountered
Trench Backfilled
T-32 0.0 - 3.0' CoILN_ ium
P_2orlVgraded SAND (SP): dark brown, silty, moist,
loose
3.0 - 4.5' Bcdroc�Formation
Well -graded SAND (4W): orange, fine- to coarse-
grained, moist, very dense
Total Depth = 4.5'
No Groundwater Encountered
Trench Backfilled
T-33 0.0 - 2.0' Colluvium
Silty SAND (SW): brown, fine- to medium -grained,
moist, loose
2.0 - 4.0' Bedsk. Pauba Formation
Poo�aded SAND (SP): yellow grey brown, medium -
grained, moist, slightly dense
4.0 - 6.5' SILT Q: light grey brown, very fine-grained, well -
indurated, slightly damp, dense
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US HOMES May 6, 1998
' RedhawWTRs 23066-5 & 23067 J.N. 163-98
Page A-13
' Test Pit
Number Depth D s ription
' Total Depth = 6.5 feet
No Groundwater Encountered
Trench Backfilled
T-34 0.0 - 2.0' Colluvium
Well -graded SAND (SWI: dark brown, fine-grained,
moist to wet, loose
2.0 - 5.0' PoorlygradedSAND (SP) with some -Clay: brown, moist
to wet, loose
5.0 - 8.0' Bedrock- Pauha Formation
' Poorly gr
aded SAND (S): orange grey brown, medium -
grained, very moist, loose
' Caving
Total Depth = 8.0 feet
' No Groundwater or Seepage (visible water 100 feet
upstream)
Trench Backfilled
' T-35 0.0 - 2.0' Colluvium
' Well -graded SAND (SW): dark brown, fine-grained,
moist, loose
2.0 - 3.0' Poorly graded_SAND =—w-ithsome Clay: orange grey
' brown, medium -grained, moist, loose
3.0 - 5.0' Bedrock- PauhaFormation
Poorlygraded SAN) (SPI: orange grey brown, medium -
grained, moist, dense
' Total Depth = 5.0 feet
No Groundwater Encountered
Trench Backfilled
' T-36 0.0 - 3.0' Colluvium
'
Well -graded SAND (51 dark brown, fine- to medium -
grained, moist, loose
@ --4.0' Bedrock: Pauba Formation
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Redhawk/TRs 23066-5 & 23067 J.N. 163-98
Page A-14
Test Pit
Number I2epth DescripliQn
3.0 - 4.5' Well -graded SAND (SM� with some Clay: orange, fine -
to medium -grained, clay grading to no clay, some gravel
and cobbles up to 4 inches, moist, extremely dense
(massive) with cobbles
Total Depth = 4.5 feet
No Groundwater Encountered
Trench Backfilled
T-37 0.0 - 3.0' C01111vium
Well -,graded SAND (S: dark brown, fine- to medium -
grained, moist, loose
3.0 - 4.0' Bedrock Pauba Formation
Poorly graded SAND (SP): orange brown, fine- and
medium -grained, moist, loose
4.0 - 6.0' SILT --(ML): light brown, fine-grained with some
medium -grained, well -indurated, dry, very dense
Total Depth = 6.0 feet
No Groundwater Encountered
Trench Backfilled
T-38 0.0 - 4.5' Bedrock- P-auha Formation
WelL-graded SAND (SWI: dark brown, fine- to medium -
grained, moist, loose
4.5 - 6.5' Well -graded SAND (CW): orange brown, fine- to
medium -grained, moist, loose
6.5 - 8.0' Bedrock Pauba Formation
Well -graded SAND (,SWI: brown/grey, moist, medium
dense
8.0 - 9.0' Well -graded SAND (SWI: brown/grey, moist, medium
dense to dense
Total Depth = 9.0 feet
No Groundwater Encountered
Trench Backfilled
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US HOMES
Redhawk/TRs 23066-5 & 23067
Test Pit
May 6, 1998
J.N. 163-98
Page A-15
Number Depth
Description
T-39 0.0 - 2.0'
Colluvium
Well --g aded SAND(SWI: dark brown, fine- to medium -
grained, moist, loose
2.0 - 6.0'
Poorly graded SAND (SPI: brown slightly orange, fine -
and medium -grained, moist, loose, occasional cobble
6.0 - 9.0'
Bedrock- Pauha Formation
SIT "T (MT. tan/light brown, very fine- to fine-grained,
well -indurated, micaceous, moist, loose to medium dense
Total Depth = 9.0 feet
No Groundwater Encountered
Trench Backfilled
T-40 0.0 - 3.0' Colluvium
Wel-gad d SND (SWI: dark brown, fine- to medium -
grained, moist, loose
3.0 - 5.0' Well -graded SANT) (S): brown slightly orange, fine -
to medium -grained, moist, loose
5.0 - 7.0' Bedrock Pauha Formation
Well- graded SAND (4W): orange brown, fine- to
medium -grained, moist
7.0 - 8.0' SILT (ML : tan, fine-grained, well -indurated, moist
8.0 - 9.0' SILT -(ML): tan, fine-grained, well -indurated, micaceous,
moist, dense
Total Depth = 9.0 feet
No Groundwater Encountered
Trench Backfilled
T-41 0.0 - 2.0' Colluvium
Silty -SAND (,SM): brown, medium -grained, moist, loose
2.0 - 5.0' Poorly graded SAND (Sp): orange brown, fine- to
medium -grained, moist, loose
5.0 - 8.5' Bedrock• Pauha Formation
Poorly gradedSAND (SP): brown, fine- to medium -
grained, moist, moderately dense
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11
US HOMES May 6, 1998
Redhawk/TRs 23066-5 & 23067 J.N. 163-98
Page A-16
Test Pit
Number Depth Description
Total Depth = 8.5 feet
No Groundwater Encountered
Trench Backfilled
T-42 0.0 - 3.0' Colluvium
Silty SAND (ASMI: dark brown, fine- to medium -grained,
moist, loose
3.0 - 4.0' Clayey SAND (SMI: orange brown, fine- to medium -
grained, granitic cobbles, moist, medium dense, gravel
5.0 - 6.0' Bedrock: Pauba Formation
Well -graded SAND (SW): orange brown, fine- to
medium -grained, moist, dense
Total Depth = 6.0 feet
No Groundwater Encountered
Trench Backfilled
T-43 0.0 - 8.0' Bedrock: Pauba Formation
Poorly graded SAND (SPI: tan, fine-grained, moist, loose
on top, density increasing with depth to medium dense
Total Depth = 8.0 feet
No Groundwater Encountered
Trench Backfilled
T-44 0.0-1.01 Colluvium
Silty SAND (SMI: dark brown, fine- to medium -grained,
moist, loose
1.0 - 3.0' Bedrock: Pauba Formation
Poorly graded SAND (SPI: orange brown, fine- to
medium -grained with some granitic cobbles to 4 inches,
some clay, moist, loose
3.0 - 4.0' Clayey SAND (SCI: dark brown, fine-grained, moist,
loose
4.0 - 8.0' Poorlygraded SAND (SPI: brown, fine- to medium -
grained, moist, moderately dense with some clay
8.Ot' SiltySAND (SM):'brown, fine- to very fine-grained,
moist, medium dense (equipment could not go deeper
due to steepness of slope)
US HOMES
Redhawk/TRs 23066-5 & 23067
Test Pit
NtLmher Dep-th Description
Total Depth = 8.0 feet
No Groundwater Encountered
Trench Backfilled
May 6, 1998
J.N. 163-98
Page A-17
T-45 0.0 - 3.0' Collum
Well -graded SAND (SWI: dark brown, fine- to medium -
grained, moist, loose
3.0 - 7.0' Bedrock- Pauba Formation
Poorly gmded SAND (SP) with fine Gray& orange
brown, medium -grained, moist, loose
7.0 - 8.0' Well-gradad SAND NW): orange brown to brown,
medium- to coarse-grained, very rounded gravel
Total Depth = 8.0 feet
Groundwater @ 8.0 feet (caving)
Trench Backfilled
�,edt30�olo'.J, 7,e�.,3010�
I
1
APPENDIX B
' LABORATORY TEST CRITERIA
LABORATORY TEST DATA
1
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' PETRA GEOTECHNICAL, INC.
J.N. 163-98 May 6, 1998
k
0
1
LI
Soil -Classification
Soils encountered within the exploration borings and test pits were initially classified in the field in general
accordance with the visual -manual procedures of the Unified Soil Classification System (Test Method ASTM
D2488-84). The samples were re-examined in the laboratory and the classifications reviewed and then revised where
appropriate. The assigned group symbols are presented in the boring and test pit logs, Appendix A.
Laboratory -Maximum Dry Density
Maximum dry density and optimum moisture content were determined for selected samples of soil and bedrock
materials in accordance with ASTM Test Method D1557-91. Pertinent test values are given on Plate B-1.
Expansion -Potential
Expansion index tests were performed on selected samples of soil and bedrock materials in accordance with Uniform
Building Code (UBC) Standard Test No. 18-2. Expansion potential classifications were determined from UBC
Table 18-1-B on the basis of the expansion index values. Test results and expansion potentials are presented on
Plate B-1.
WIM11W I' rX.To 1M
Chemical analyses were performed on selected samples of soil and bedrock materials to determine soluble sulfate
contents. These tests were performed in accordance with California Test Method No. 417. Test results are included
on Plate B-1.
1n-Situ_Moisture_and Density
Moisture content and unit dry density of in-place soil and bedrock materials were determined in representative strata.
Test data are summarized in the boring logs, Appendix A and on Plate B-2.
' Consolidation
Consolidation tests were performed in general accordance with ASTM Test Method D2435-80. Axial loads were
applied in several increments to a laterally restrained 1 -inch -high sample. Loads were applied in a geometric
progression by doubling the previous load and the resulting deformations were recorded at selected time intervals.
The test samples were inundated at a surcharge loading approximately equal to the existing or proposed total
overburden pressures in order to evaluate the effects of a sudden increase in moisture content (hydroconsolidation
potential). Results of these tests are graphically presented on Plates B-3 and B-6.
PETRA GEOTECHNICAL, INC.
J.N. 163-98 May e, 1998
1
1
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t
LABORATORY MAXLMUM DRY DENSITY`
Test Pit
Boring
Number
Depth
(ft.)
I
Soil Type
Optimum
Moisture (%)
Maximum
Dry Density
pcf)
T-1
1.0
A - Clayey SAND (SC)
8.0
130.0
T-1
3.0
B - Silty SAND (SM)
8.0
129.0
T-5
2.0
C - SAND (SP -SW)
7.0
131.0
2-1
10.0 1
D - Silty SAND (SM) 1
8.0
130.0
EXPANSION INDEX TEST DATA'
Soil Type
Expansion Index
Expansion Potential'
A - Clayey SAND (SC)
7.0
Very Low
B - Silty SAND (SM)
5.0
Very Low
C - SAND (SP -SM)
7.0
Very Low
TP -3 Q 2.0'
126.0
Hiah
SOLUBLE SULFATES°
Soil Tye
Sulfate Content (%)
A- Clayey SAND (SC)
0.009
D - Silty SAND (SM)
0.013
(l) PER TEST METHOD ASTM D 1557-91
(2) PER UNIFORM BUILDING CODE STANDARD TEST 18-2
(3) PER UBC TABLE 18 -I -B
(4) PER CALIFORNIA TEST METHOD NO. 417
PLATE B-1
PETRA GEOTECHNICAL, INC.
J.N. 163-98 May 6, 1 998
Test Pit
Number
Depth
ft.)
Moisture
%)
Dry Density
I (ef)
TP -1
2.0
11.7
115.5
TP -1
4.0
10.0
110.0
TP -1
6.0
11.5
112.7
TP -2
2.0
16.2
103.0
TP -2
4.0
13.5
108.5
TP -2
6.0
18.6
101.1
TP -3
2.0
14.3
117.5
TP -3
4.0
20.5
102.2
TP -3
6.0
12.6
108.2
TP -5
2.0
18.5
108.0
TP -5
4.0
24.9
98.5
TP -5
6.0
23.0
99.2
TP -6
2.0
16.0
105.7
TP -6
4.0
8.1
108.4
TP -6
6.0-
12.1
103.7
TP -7
2.0
15.4
87.7
TP -7
4.0
15.2
112.2
TP -8
2.0
13.5
103.7
TP -8
4.0
15.2
115.9
TP -9
2.0
12.9
114.7
TP -9
4.0
9.2
108.7
PETRA GEOTECHNICAL, INC.
' J.N. 163-98
n
L
PLATE B-2
May 69 1998
0.0
1
2
3
E
7
3
9
in
SAMPLE
LOCATION
MATERIAL
DESCRIPTION
INITIAL
INUNDATED
DENSITY
(Pefl
MOISTURE
(%)
SATURATION
(%)
LOAD
(kst)
B-1@20.0
Silty Sand (SM)
115.8
16.0
95
0.30
Ulm
M.
0.18 0.35 0.7 1.4 2.8 5.6 11.2 22.4 44.8
VERTICAL STRESS - kips per square foot
J.N. 163-98 May, 1998
CONSOLIDATION TEST RESULTS
PETRA GEOTECHNICAL, INC. PLATE B-3
SAMPLE
LOCATION
MATERIAL
DESCRIPTION
SAL
INUNDATED
DENSITY
(Pof)
MOISTURE
(%)
SATURATION
(%)
LOAD
(tsf)
i B-2 ® 15.0
Silty Sand (SM)
113.2
19.2
106
0.30
0.0 0.18 0.35 0.7
1.0
2.0
3.0
z
0
F
a 4.0—
z
.0
J
O
z
z
U
U
z 5.0
z
u
c
z
c
6.0
7.0
8.0
9.0
10.
1.4 2.8 5.6 11.2 22.4 44.8
VERTICAL STRESS - kips per square foot
J.N. 163-98 May, 1998
CONSOLIDATION TEST RESULTS
PETRA GEOTECHNICAL, INC. I PLATE B-4
1
1
1
1
1
1
1
1
10.0
Silty Sand (SM)
113.6
SAMPLE
LOCATION
MATERIAL
DESCRIPCION
1.20
D�C17A1-
DdL1NDA1'ED
DINSITY
(pcf)
MOISTURE
(%)
SATURATTON
(%)
LOAD
(tsf)
• B-3 @
�����_■■■■��►
!M■■■■■��mm■■■■■
MENNIMEMEN
IMMENOMME
MOMMOM
MEMO
1
1
g Oil ..
„
CONSOLIDATION
PETRA GEOTECHNICAL, INC.
10.0
Silty Sand (SM)
113.6
9.2
51
1.20
I
I
' APPENDIX C
STANDARD GRADING SPECIFICATIONS
1
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t PETRA GEOTECHNICAL, INC.
J.N. 163-98 May 6, 1998
These specifications present the usual and minimum requirements for grading
operations performed under the control of Petra Geotechnical, Inc.
No deviation from these specifications will be allowed, except where specifically
superseded in the preliminary geology and soils report, or in other written
communication signed by the Soils Engineer and Engineering Geologist.
A. The Soils Engineer and Engineering Geologist are the Owner's or
Builder's representative on the project. For the purpose of these
specifications, supervision by the Soils Engineer includes that inspection
performed by any person or persons employed by, and responsible to,
the licensed Civil Engineer signing the soils report.
' B. All clearing, site preparation, or earthwork performed on the project
shall be conducted by the Contractor under the supervision of the Soils
Engineer.
C. It is the Contractor's responsibility to prepare the ground surface to
receive the fills to the satisfaction of the Soils Engineer and to place,
spread, mix, water, and compact the fill in accordance with the
specifications of the Soils Engineer. The Contractor shall also remove all
material considered unsatisfactory by the Soils Engineer.
D. It is also the Contractor's responsibility to have suitable and sufficient
compaction equipment on the job site to handle the amount of fill being
placed. If necessary, excavation equipment will be shut down to permit
completion of compaction. Sufficient watering apparatus will also be
provided by the Contractor, with due consideration for the fill material,
rate of placement, and time of year.
E. A final report shall be issued by the Soils Engineer and Engineering
Geologist attesting to the Contractor's conformance with these
specifications.
A. All vegetation and deleterious material such as rubbish shall be disposed
of offsite. This removal shall be concluded prior to placing fill.
- Page 1 -
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B. Soil, alluvium, or bedrock materials determined by the Soils Engineer as
being unsuitable for placement in compacted fills shall be removed and
wasted from the site. Any material incorporated as a part of a
compacted fill must be approved by the Soils Engineer.
C. After the ground surface to receive fill has been cleared, it shall be
scarified, disced, or bladed by the Contractor until it is uniform and free
from ruts, hollows, hummocks, or other uneven features which may
prevent uniform compaction.
The scarified ground surface shall then be brought to optimum moisture,
mixed as required, and compacted as specified. If the scarified zone is
greater than 12 inches in depth, the excess shall be removed and placed
in lifts restricted to 6 inches.
Prior to placing fill, the ground surface to receive fill shall be inspected,
tested, and approved by the Soils Engineer.
D. Any underground structures such as cesspools, cisterns, mining shafts,
tunnels, septic tanks, wells, pipe lines, or others are to be removed or
treated in a manner prescribed by the Soils Engineer.
E. In order to provide uniform bearing conditions in cut/fill transition lots
and where cut lots are partially in soil, colluvium, or unweathered
bedrock materials, the bedrock portion of the lot extending a minimum
of 3 feet outside of building lines shall be overexcavated a minimum of
3 feet and replaced with compacted fill. (Typical details are given on
Plate SG -1.)
' A. Any material imported or excavated on the property may be utilized in
the fill, provided each material has been determined to be suitable by
the Soils Engineer. Roots, tree branches, and other matter missed
during clearing shall be removed from the fill as directed by the Soils
Engineer.
' B. Rock fragments less than 6 inches in diameter may be utilized in the
fill provided:
' 1. They are not placed in concentrated pockets.
- Page 2 - U6
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2. There is a sufficient percentage of fine grained material to surround
the rocks.
3. The distribution of rocks is supervised by the Soils Engineer.
C. Rocks greater than 6 inches in diameter shall be taken offsite or placed
in accordance with the recommendations of the Soils Engineer in areas
designated as suitable for rock disposal. (A typical detail for Rock
Disposal is given in Plate SG -2.)
D. Material that is spongy, subject to decay, or otherwise considered
unsuitable shall not be used in the compacted fill.
E. Representative samples of materials to be utilized as compacted fill
shall be analyzed by the laboratory of the Soils Engineer to determine
their physical properties. If any material other than that previously
tested is encountered during grading, the appropriate analysis of this
material shall be conducted by the Soils Engineer as soon as possible.
F. Material used in the compacting process shall be evenly spread,
watered, processed, and compacted in thin lifts not to exceed 6 inches
in thickness to obtain a uniformly dense layer. The fill shall be placed
and compacted on a horizontal plane, unless otherwise approved by
the Soils Engineer.
G. If the moisture content or relative density varies from that required by
the Soils Engineer, the Contractor shall rework the fill until it is
approved by the Soils Engineer.
H. Each layer shall be compacted to 90 percent of the maximum density
in compliance with the testing method specified by the controlling
governmental agency. (In general, ASTM D 1557-78, the five -layer
method, will be used.)
If compaction to a lesser percentage is authorized by the controlling
governmental agency because of a specific land use or expansive soils
condition, the area to received fill compacted to less than 90 percent
shall either be delineated on the grading plan or appropriate reference
made to the area in the soils report.
All fills shall be keyed and benched through all topsoil, colluvium,
alluvium or creep material, into sound bedrock or firm material where
- Page 3 -
I
' the slope receiving fill exceeds a ratio of 5 horizontal to 1 vertical, in
'accordance with the recommendations of the Soils Engineer.
a
J. The key for side hill fills shall be a minimum of 15 feet within bedrock
' or firm materials, unless otherwise specified in the soils report. (See
detail on Plate SG -3.)
K. Subdrainage devices shall be constructed in compliance with the
ordinances of the controlling governmental agency, or with the
recommendations of the Soils Engineer or Engineering Geologist.
(Typical Canyon Subdrain details are given in Plate SG -4.)
L. The contractor will be required to obtain a minimum relative
compaction of 90 percent out to the finish slope face of fill slopes,
buttresses, and stabilization fills. This may be achieved by either
overbuilding the slope and cutting back to the compacted core, or by
direct compaction of the slope face with suitable equipment, or by any
other procedure which produces the required compaction.
M. All fill slopes should be planted or protected from erosion by other
methods specified in the soils report.
N. Fill -over -cut slopes shall be properly keyed through topsoil, colluvium
or creep material into rock or firm materials, and the transition shall be
stripped of all soils prior to placing fill. (See detail on Plate SG -7.)
IV. CU_LSLQeES
A. The Engineering Geologist shall inspect all cut slopes at vertical
intervals not exceeding 10 feet.
B. If any conditions not anticipated in the preliminary report such as
perched water, seepage, lenticular or confined strata of a potentially
adverse nature, unfavorably inclined bedding, joints or fault planes are
encountered during grading, these conditions shall be analyzed by the
Engineering Geologist and Soils Engineer, and recommendations shall
be made to treat these problems. (Typical details for stabilization of a
portion of a cut slope are given in Plates SG -5 and SG -8.)
- Page 4 -
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' STANDARD GRADING SPECIFICATIONS
C. Cut slopes that face in the same direction as the prevailing drainage
shall be protected from slope wash by a nonerodible interceptor swale
placed at the top of the slope.
' D. Unless otherwise specified in the soils and geological report, no cut
slopes shall be excavated higher or steeper than that allowed by the
ordinances of controlling governmental agencies.
' E. Drainage terraces shall be constructed in compliance with the
ordinances of controlling governmental agencies, or with the
' recommendations of the Soils Engineer or Engineering Geologist.
' V. GRADING CONTROL
' A. Inspection of the fill placement shall be provided by the Soils Engineer
during the progress of grading.
B. In general, density tests should be made at intervals not exceeding 2
feet of fill height or every 500 cubic yards of fill placed. This criteria
will vary depending on soil conditions and the size of the job. in any
' event, an adequate number of field density tests shall be made to verify
that the required compaction is being achieved.
' C. Density tests should also be made on the surface material to receive fill
as required by the Soils Engineer.
' D. All cleanouts, processed ground to receive fill, key excavations,
subdrains, and rock disposals must be inspected and approved by the
' Soils Engineer or Engineering Geologist prior to placing any fill. It
shall be the Contractor's responsibility to notify the Soils Engineer
when such areas are ready for inspection.
t
VI. CONSTRUCTION CONSIDERATIONS
' A. Erosion control measures, when necessary, shall be provided by the
Contractor during grading and prior to the completion and construction
' of permanent drainage controls.
' B. Upon completion of grading and termination of inspections by the
Soils Engineer, no further filling or excavating, including that necessary
- Page 5 -
' STANDARD -GRADING SPECIFICATIONS
' for footings, foundations, large tree wells, retaining walls, or other
' features shall be performed without the approval of the Soils Engineer
or Engineering Geologist.
' C. Care shall be taken by the Contractor during final grading to preserve
any berms, drainage terraces, interceptor swales, or other devices of
permanent nature on or adjacent to the property.
1
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- Page 6 -
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CUT LOT
UNSUITABLE MATERIAL EXPOSED IN PORTION OF CUT PAD
ORIGINAL GRADE
!�_ f MATERIAL aEDROCK
UygUITA6L .NEATt1ERE0
---�'r COLLUVW'�
M� (D1
aCIL. �Or I
TOP-. S' MIn
_,— PROPOSED GRADE
w PACTED
PLL (F) �� l
COWMTE ' SADFIOCK OR OVERFXCAVAT-c
AND REC-DWACT
APPROVEDFOUNDATION MATERIAL
TYPICAL BENCHING
DEPTH OF FILL (F1
Footing Depth to 3 feet -..Equal Depth
3 to 6 toot ........ }eat
Greater than S feet -__ ...One-half the thicknass of fin placed on the
'FILL- portion (F) to 15 feet maximum
COMPACTED
FILL
CUT -FILL TRANSITION LOT
E'
PROPOSED GRADE
i
r �
I OLLJ 0C, i
j0115OtEfiEC
�EAZN
TYPICAL BENCHING
ORIGINAL
Y GROUND
i
' Or
i
I�
OVEREXCAVATI:
ANL RECOMFACT
COMPETENT BEDROCK CR
APPROVED FGUNDAT!ON MATERIAL
a 30�
' I CUT LOTS AND CUT -FILL TRANSITION LOTS PLATE SG -1
FINISHED GRADE
I
CLEAR AREA FOR FOUNDATIONS, 13'
�UTWTIES. AND SWIMMING POOLS- I —
i
SLOPE FACE
4 15 \
\� 15 STREET
WINDROW
5' OR BELOW DEPTH
OF DEEPEST UTILITY TRENCH,
WHICHEVER IS GPEATER.
TYPICAL WINDROW DETAIL (END VIEW1
HORIZONTALLY PLACED
co.MFIACTED FILL
6 l'O 3 INCH LIFTS
15'
PROFILE VIEW
TYPICAL ROCK DISPOSAL DETAIL
GRANDULAR SOIL FLOODED
TO FILL VOIDS
PLPL.bT�-z
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F
1
1
11
l l
FINISHEC GRADE
COMPACTED FILL
TOE OF SLOPE AS SHOWN
ON GRADING PLAN -` i OEp PO i
6
NATU)POGRA
/.SOQSOU.,
l�
i PROJECTION
-t
2' MM. DC W NSLOPE
KEY CEPTH
2'G mir.
- 15"' MINIMUM -
SASE KEY WIDTH
TYPICAL EENCHING
COMPETENT BEDROCK OR APPROVED
FOUNOAT;ON MATERIAL
?JG IS
T NECESSARY;
NOTE: HWHERE OWEVER. FILL IJRAL S SLOPE
5Z PLACE ON CCMPRESS BLEGRADIENT !S 5:1 OR LESS IOR UNSO TAR' -- MATEFIAL.
FILL SLOPE ABOVE NATURAL SLOPE PLATE SG -3
' NATURAL GROUND
\TYPICAL
UNSUITABLE MATERIALTOPSOIL. ALLUVNM, COLLUVIUM�-.�
1
2%
SEE DETAIL
NOTE: FINAL 20 FEET OF PIPE AT OUTLET
SHALL BE NON -PERFORATED.
DEPTH AND BEDDING MAY
VARY WITH PIPE .AND LOAD
CHARACTERISTICS.
0
COMPETENT BEDROCK OR
APPROVED FOUNDATION
FILTER MATERIAL- MINIMUM OF 9
CUBIC FEET PER LINEAL FOOT.
SEE PLATE SG -6 FOR FILTER
MATERIAL SPECIFICATIONS.
"TERNA,E IN LIU OF
FILTEP MATEPIAL:
9 CUBIC FEET PER LINEAL FOOT OF
OPEN-ORAOED GRAVEL ENCASED IN
FILTER FABRIC. SEE PLATE SG -6 FOR
GRAVEL SPECIFICATIONS.
FILTER FABRM SHALL Be- MIRAFI
14LH OR APPROVED EQUAL.
18"min--'�--'I
/MINIMUM6-INCH DIAMETER PVC SCHEDULE 40, OR ABS
SDR - 35 WITH A MINIMUM OF 18 PERFORATIONS PER
LINEAL FOOT IN BOTTOM HALF OF PIPE. PIPE TO BE LAID
WITH PERFORATIONS DOWN.
FOR CONTINUOUS RUNS IN EXCESS OF 500 FEE- USE
&INCH DIAMETER PIPE.
'
PLATE
CANYON SUBDRAIN DETAIL
1
1
1
1
FINISHED,
GRADE
2'nin.
T"—
T� TOP OF BACK CUT
--- 15' MIN.
4- SJB=RAb4
Iy
A-
30' MAXIMUM SPACING 9>
3- EUBDRAIN
2%n:n --�
WIDTH VARIES (15' MIN.)!
I
.SZE DETAit.
PLATE 5G -o-
TYPICAL BENCHING
NOTES:
1. MaXimu.m var:icaf spacing Of perforated pipe of 30 eeF.
2. Maximum horizontai distance between non -perforated
pipe of 100feet outlets.
3. Minimum gradient of one percent of all perforate-, :ipe and
non-pertorated pipe and nor. -perforate -,cutlet pipe.
'0Q' MAX
i
OUTLET PPE (TYPICAL)
\ FERFOn.aTE7 rIPE JYPic AL)
' I BUTTRESS OR STABILIZATION FILL DETAIL PLATE SG -5 I
u
I
'
SLOPE FACE^� APPROVED FILTER MATERIAL. \5 CUSIG FEET PEP, LINEAR F007,
WITHCUT FILTER FABRIC, 3 CUBIC
AFI?
/`•. `,: , WITH FABRIC.
Flo,2 % MINIMUM " 4- NCH PERFORATED PIPE WITH
PERFORATIONS DOWN. MINIMUM
' 2i, GRADE TO CUTLET PIPE,
4 -INCH NON -PERFORATED PIPE.
MINIMUM 27/. GRADE TO OUTLET. I
I
' �.--- APPROVEO ON SITE MATERIAL PER SOILS ENCINEER I
/ COMPACTED TO A MINIMUM OF 905'. MAXIMUM CENSITY.
E r
' — A -INCH NON -PERFORATED PIPE.
12" mh. 1•--
'SECTION A -A
PIPE SPECIFICATIONS
1. 4-INC4 MIMMUM DIAMETER. PVC SCHEDULE 40. OR ASS SOR-35.
2. MINIMUM 16 PERFORATIONS PER FOOT ON BOTTOM ONE--HIRO OF PIPE.
FILTER MATEPIAI SPECIFiCATION5
CLASS 2 PERMEABLE FILTER MATERIAL P5; CALTRANS STANCARD SPECIFICATION
CLASS 2
i
' STEVE SIZE PERCENT PASSINu
t -INCH 100
go -loo
3/4 -INCH 40-100
3/8 -INCH 25-40
' NO. 4 1S-33
NO. 8 5-15
NO. -30 0-7
NO. -SO 0-3
NO. 270
ALTERNATE: OPEN GRADED GRAVEL ENCASED IN F1' -TER FABRIC. ;MIRAFI 1a0N OR EQUAL)
OPEN -GRADED
' SIEVE SIZ PER' ;zNT mASSING
1 7/2-'NGH 35.40
1 -INCH 0-17
' I 3/4 -INCH
3/8 -INCH
NO. 200
' BUTTRESS OR STABILIZATION FILL SUBDRA!N PLATE SG -6
-r m m m m m mm m m
COMPAC I ED FILL
CUT/FILL "CONTACT �' aka' 04 _ l
SHOWN ON GRADING PLAN--
CIROF
a -
SHOWN • AS-DUtLr%ON
REMOVE ALL TOPSOIL, COLLUVIUM, OR
0U1-uNttld'
' 4' TYPICAL
CREEP MATERIAL FROM TRANSITION-,
�OYS �
NATURAL��`
y
I—PIT
2V-
II--�-
10' TYPICAL
"
TOPOGRAPHY �'
(VARIES
I
l l
MINIMUM .-_�
CUT
OR PER SOILS FNGtNEER
DEDROCH OR APPROWD FOUNDATION MATERIAL
I
I
I
I
I
v
I
1
I
NATURAL TOPOGRAPHY
I I
/ / I
I I I
/I
FINISHED GRADE
4' TYP.
VARIES 10'
TYF.
/ 2-�+
�-� COMPACTED FILL
w
BEDROCK OR APPROVED FOUNDATION MATERIAL
NOTE: 1. SUSDRAINS NOT REQUIRED UNLESS SPECIFIED.
2. "W- SHALL SE EQUIPMENT WIDTH (15') FOP. SLOPE HEIGHTS LESS THAN 3C FEET.
FOR SLOPE HEtOHTS GREATER THAN 30 FEET "W' SHALL SE DETERMINED SY
THE PROJECT SOILS ENGINEER.
' STABILIZATION FILL DETAIL PLATE SG -8
1
1
1
1
1
1
PROPOSED CUT LOT
-T
INSTALL 6-INCHTME S
PER. PLATES SC -4 AND
EXISTING TOPOGRAPHY
-PRO=OSED DAYLIGHT CUT
RECONSTRUCT AT
1.5:1 OR FLATTER
�K
COMPACTED
FILL
W J�
G
Gy'
0�
i
�W
NOTE: -W- SHALL BE 10 FEET MINIMUM 0.9 AS OET£RMINED
3Y THE PROJECT SOILS ENGINEER
-�,;23010 o(o , s. 'T�c%30e7
SHEAR KEY ON DAYLIGHT CUT LOTS
PLATE SG -9
I
OF RUC: DISPOSAL
FIMSB 10' blMN
GRADE
Oaa.cOaa.c Oac.cCcc.c aaa�o�3caea Ccc.cCCic«d,.
' 3M Oc,✓>aQOaooQOa>c� Cooec3L�aaonClocooCca.n 4-�;.
QaGocOaG�cCoa.nCca.,�:Coc.�.a0oc.o ter.
sW •
1]ao>dJaaod Qoa.cCaa.o CoOoc�oa.n . r:
'
i ROCY HLA -N= (TYP)
.,: :niy ",,< I]60vdQ6Ovc�60vn�160«G .;rsL..:
COMPETED: r '`�%r ',,k"• MRS.
PER SOILS ENGRMER�'
1
1
1
SECTION A -A'
FNISY SLOPE F4CE
I
T ROCK BLA.NKEr (TYP)
I" NUN. Qo
LDYM OFROr1CDiSPOS.0
to MLti.
" """�QoGeaQ000aOr�c.,cCnc�.c
GoaooOar�.�, Ooaoo
"^"O�coaGor -o L�ao.aCl^ Goo C1oG�aDao.d
.- "O�c.oOaG.a Qn,codQoQod daaodC�ac.ra CioG>cC�o��n
2' MIN.
C
SECTION B -B'
dATERIAL
PER SOILS ENGINEER
I
1
1
L
APPENDIX D
SLOPE STABILITY CALCULATIONS
u
L
1
I
1
' PETRA GEOTECHNICAL, INC.
J.N. 163-98 May 6, 1998
1
1
1
1
*' PCSTABLSM '•
by
Purdue University
--Slope Stability Analysis --
Simplified Janbu, Simplified Bishop
or Spencer's Method of Slices
Run Date: 05-06-98
Time of Run: 1:07pm
Run By: CB
Input Data Filename: C:FILL-1.IN
Output Filename: C:FILL-1.OUT
Plotted Output Filename: C:FILL-l.PLT
PROBLEM DESCRIPTION Stability of 60 -foot -high, 2:1 fill
slope - Static Analysis
BOUNDARY COORDINATES
5 Top Boundaries
5 Total Boundaries
Boundary
X -Left
Y -Left
X -Right
Y -Right
Soil Type
No.
(ft)
(ft)
(ft)
(ft)
Below Bnd
1
.00
20.00
20.00
20.00
1
2
20.00
20.00
80.00
50.00
1
3
80.00
50.00
86.00
50.00
1
9
86.00
50.00
196.00
80.00
1
5
196.00
80.00
200.00
80.00
1
ISOTROPIC SOIL PARAMETERS
1 Type(s) of Soil
Soil Total Saturated Cohesion Friction Pore Pressure Piez.
Type Unit Wt. Unit Wt. Intercept Angle Pressure constant Surface
No. (pcf) (pcf) (psf) (deg) Param. (psf) No.
1 130.0 130.0 100.0 39.0 .00 .0 0
A Critical Failure Surface Searching Method, Using A Random
Technique For Generating Circular Surfaces, Has Been Spec_fied.
200 Trial Surfaces Have Been Generated.
10 Surfaces Initiate From Each Of 20 Points Equally Spaced
Along The Ground Surface Between X = 15.00 ft.
and X = 25.00 ft.
Each Surface Terminates Between X = 190.00 ft.
and X = 200.00 ft.
Unless Further Limitations Were Imposed, The Minimum Elevation
At Which A Surface Extends Is Y = .00 ft.
I
1
E
U
1
11
15.00 ft. Line Segments Define Each Trial Failure Surface.
' ' Safety Factors Are Calculated By The Modified Bishop Method ' '
Failure Surface Specified By 13 Coordinate Points
Point
X -Surf
Y -Surf
No.
(ft)
(ft)
1
24.47
22.24
2
39.40
23.73
3
54.25
25.86
4
68.99
28.63
5
83.60
32.03
6
98.05
36.06
7
112.31
40.71
8
126.36
45.96
9
140.17
51.82
10
153.71
58.27
11
166.97
65.29
12
179.90
72.88
13
190.92
80.00
Circle Center At X = -2.6 ; Y = 369.3 and Radius, 348.1
2.064 '**
Individual data on the 15 slices
Water Water Tie Tie Earthquake
Force Force Force Force Force Surcharge
Slice Width Weight Top Bot Norm Tan Hot Ver Load
No. Ft(m) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg)
1 14.9 5794.7 .0 .0 .0 .0 .0 .0 .0
2 14.8 16636.2 .0 .0 .0 .0 .0 .0 .0
3 14.7 25998.4 .0 .0 .0 .0 .0 .0 .0
4 11.0 24814.9 .0 .0 .0 .0 .0 .0 .0
5 3.6 8603.4 .0 .0 .0 .0 .0 .0 .0
6 2.4 5504.5 .0 .0 .0 .0 .0 .0 .0
7 12.0 29163.3 .0 .0 .0 .0 .0 .0 .0
8 14.3 39319.7 .0 .0 .0 .0 .0 .0 .0
9 14.0 42613.3 .0 .0 .0 .0 .0 .0 .0
10 13.8 44412.7 .0 .0 .0 .0 .0 .0 .0
11 5.8 19208.1 .0 .0 .0 .0 .0 .0 .0
12 7.7 23626.8 .0 .0 .0 .0 .0 .0 .0
13 13.3 31393.1 .0 .0 .0 .0 .0 .0 .0
14 12.9 18357.1 .0 .0 .0 .0 .0 .0 .0
15 11.0 5099.7 .0 .0 .0 .0 .0 .0 .0
Y -Axis
(ft)
# FS
a2.06 Label
b 2.07 Fill
c 2.08
d 2.08
e 2.10
f 2.11
9 2.11
h 2.12
1 2.12
1 2.12
1 Total Saturated Cohesion Friction Pore Pressure Plea.
I Unit Mt. Unit Mt. Intercept Angle Pressure Constant Surface
%ff) %ff) (pf) (deg) ParOam. (pssf) No.
D 40 80 120 160
PCSTABL5M FSmin=2.06 X -Axis (ft)
Factors Of Safety Calculated By The Modified Bishop Method
I
200
Stability of
60 -foot -high, 2:1
fill
slope - Static
Analysis
Ten Most
Critical, C:FILL-1.PLT
By:
CB 05-06-98 1:07pm
Y -Axis
(ft)
# FS
a2.06 Label
b 2.07 Fill
c 2.08
d 2.08
e 2.10
f 2.11
9 2.11
h 2.12
1 2.12
1 2.12
1 Total Saturated Cohesion Friction Pore Pressure Plea.
I Unit Mt. Unit Mt. Intercept Angle Pressure Constant Surface
%ff) %ff) (pf) (deg) ParOam. (pssf) No.
D 40 80 120 160
PCSTABL5M FSmin=2.06 X -Axis (ft)
Factors Of Safety Calculated By The Modified Bishop Method
I
200
1
1
1
1
1
t
1
1
1
" PCSTABLSM "
by
Purdue University
--Slope Stability Analysis --
Simplified Janbu, Simplified Bishop
or Spencer's Method of Slices
Run Date: 05-06-98
Time of Run: 1:08pm
Run By: CB
Input Data Filename: C:FILL-2.IN
Output Filename: C:FILL-2.0UT
Plotted Output Filename: C:FILL-2.PLT
PROBLEM DESCRIPTION Stability of 60 -foot -high, 2:1 fill
slope - Seismic Analysis
BOUNDARY COORDINATES
5 Top Boundaries
5 Total Boundaries
Boundary
X -Left
Y -Left
X -Right
Y -Right
Soil Type
No.
(ft)
(ft)
(ft)
(ft)
Below Bnd
1
.00
20.00
20.00
20.00
1
2
20.00
20.00
80.00
50.00
1
3
80.00
50.00
86.00
50.00
1
4
86.00
50.00
146.00
80.00
1
5
146.00
80.00
200.00
80.00
1
ISOTROPIC SOIL PARAMETERS
1 Type(s) of Soil
Soil Total Saturated Cohesion Friction Pore Pressure Piez.
Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface
No. (pcf) (pcf) (pst) (deg) Param. (psf) No.
1 130.0 130.0 100.0 34.0 .00 .0 0
A Horizontal Earthquake Loading Coefficient
Of .200 Has Been Assigned
A Vertical Earthquake Loading Coefficient
Of .000 Has Been Assigned
Cavitation Pressure = .0 psf
A Critical Failure Surface Searching Method, Using A Random
Technique For Generating Circular Surfaces, Has Been Specified.
200 Trial Surfaces Have Been Generated.
10 Surfaces Initiate From Each Of 20 Points Equally Spaced
I
1
1
n
1
1
U
1
1
1
1
1
1
1
1
Along The Ground Surface Between X = 15.00 ft.
and X = 25.00 ft.
Each Surface Terminates Between X = 190.00 ft.
and X = 200.00 ft.
Unless Further Limitations Were imposed, The Minimum Elevation
At Which A Surface Extends Is Y = .00 ft.
15.00 ft. Line Segments Define Each Trial Failure Surface.
• Safety Factors Are Calculated By The Modified Bishop Method '
Failure Surface Specified By 14 Coordinate Points
Point
X -Surf
Y -Surf
No.
(ft)
(ft)
1
20.26
20.13
2
34.93
23.26
3
49.53
26.72
4
64.04
30.51
5
78.47
34.62
6
92.80
39.05
7
107.02
43.81
8
121.14
48.88
9
135.14
54.27
10
149.01
59.98
11
162.75
65.99
12
176.36
72.31
13
189.81
78.94
14
191.86
80.00
Circle Center At X = -111.3 ; Y = 673.1 and Radius, 666.1
1.256 "'
Individual data on the 16 slices
Water water Tie Tie Earthquake
Force Force Force Force Force Surcharge
Slice Width Weight Top Bot Norm Tan Hor Ver Load
No. Ft(m) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg)
1 14.7 4009.8 .0 .0 .0 .0 802.0 .0 .0
2 14.6 11621.3 .0 .0 .0 .0 2324.3 .0 .0
3 14.5 18453.1 .0 .0 .0 .0 3690.6 .0 .0
4 14.4 24503.1 .0 .0 .0 .0 4900.6 .0 .0
5 1.5 2937.9 .0 .0 .0 .0 587.6 .0 .0
6 6.0 10904.4 .0 .0 .0 .0 2180.9 .0 .0
7 6.8 12107.8 .0 .0 .0 .0 2421.6 .0 .0
8 14.2 28713.2 .0 .0 .0 .0 5742.6 .0 .0
9 14.1 32473.3 .0 .0 .0 .0 6494.7 .0 .0
10 14.0 35471.3 .0 .0 .0 .0 7094.3 .0 .0
11 10.9 29340.4 .0 .0 .0 .0 5868.1 .0 .0
12 3.0 8082.8 .0 .0 .0 .0 1616.6 .0 .0
13 13.7 30399.3 .0 .0 .0 .0 6079.9 .0 .0
14 13.6 19185.7 .0 .0 .0 .0 3837.1 .0 .0
15 13.5 7655.3 .0 .0 .0 .0 1531.1 .0 .0
16 2.0 141.1 .0 .0 .0 .0 28.2 .0 .0
iko
Stability of 60 -foot -high, 2:1 fill slope - Seismic Analysis
Ten Most Critical. C:FILL-2.PLT By: CB 05-06-98 1:08pm
0 40 80 120 160 200
PCSTABL5M FSmin=1.26 X -Axis (ft)
Factors Of Safety Calculated By The Modified Bishop Method
" PCSTABLSM "
by
Purdue University
--Slope Stability Analysis --
Simplified Janbu, Simplified Bishop
or Spencer's Method of Slices
Run Date: 05-06-98
Time of Run: 1:13pm
Run By: CB
Input Data Filename: C:CUT-1
Output Filename: C:CUT-1.OUT
Plotted Output Filename: C:CUT-1.PLT
PROBLEM DESCRIPTION Stability of 40 -foot -high, 2:1 cut
slope - Static Analysis
BOUNDARY COORDINATES
5 Top Boundaries
5 Total Boundaries
Boundary
X -Left
Y -Left
X -Right
Y -Right
Soil Type
No.
(ft)
(ft)
Ift)
(ft)
Below Bnd
1
.00
20.00
20.00
20.00
1
2
20.00
20.00
60.00
40.00
1
3
60.00
40.00
66.00
40.00
1
4
66.00
40.00
106.00
60.00
1
5
106.00
60.00
150.00
60.00
1
ISOTROPIC SOIL PARAMETERS
1 Type(s) of Soil
Soil Total Saturated Cohesion Friction Pore Pressure Piez.
Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface
No. (pcf) (pcf) (Psf) (deg) Param. (psf) No.
1 130.0 130.0 590.0 36.0 .00 .0 0
A Critical Failure Surface Searching Method, Using A Random
Technique For Generating Circular Surfaces, Has Been Specified.
200 Trial Surfaces Have Been Generated.
10 Surfaces Initiate From Each Of 20 Points Equally Spaced
Along The Ground Surface Between X = 15.00 ft.
and X = 25.00 ft.
Each Surface Terminates Between X = 110.00 ft.
and X = 130.00 ft.
Unless Further Limitations Were Imposed, The Minimum Elevation
At Which A Surface Extends Is Y = .00 ft.
15.00 ft. Line Segments Define Each Trial Failure Surface.
• Safety Factors Are Calculated By The Modified Bishop Method • •
Failure Surface Specified By 9 Coordinate Points
Point
X -Surf
No.
(ft)
1
19.74
2
34.62
3
49.61
4
64.38
5
78.59
6
91.91
7
104.03
8
114.69
9
120.49
Circle Center At X
Y -Surf
(ft)
20.00
18.11
18.47
21.10
25.91
32.81
41.64
52.20
60.00
39.7 ; Y = 117.3 and Radius, 99.3
•*• 3.082 •••
Individual data on the 12 slices
Water Water Tie Tie Earthquake
Force Force Force Force Force Surcharge
Slice Width Weight Top Bot Norm Tan Hor Ver Load
No. Ft(m) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg)
1 .3 .6 .0 .0 .0 .0 .0 .0 .0
2 14.6 8776.1 .0 .0 .0 .0 .0 .0 .0
3 15.0 24890.8 .0 .0 .0 .0 .0 .0 .0
4 10.4 24317.1 .0 .0 .0 .0 .0 .0 .0
5 4.4 10990.0 .0 .0 .0 .0 .0 .0 .0
6 1.6 3919.5 .0 .0 .0 .0 .0 .0 .0
7 12.6 31693.6 .0 .0 .0 .0 .0 .0 .0
8 13.3 35077.1 .0 .0 .0 .0 .0 .0 .0
9 12.1 29568.1 .0 .0 .0 .0 .0 .0 .0
10 2.0 4321.9 .0 .0 .0 .0 .0 .0 .0
11 8.7 13676.2 .0 .0 .0 .0 .0 .0 .0
12 5.8 2941.1 .0 .0 .0 .0 .0 .0 .0
Y -Axis
(f t)
0 30 60 90 120 150
PCSTABL5M FSmin=3.08 X -Axis (ft)
Factors Of Safety Calculated By The Modified Bishop Method
Stability of 40 -foot -high,
2:1 cut slope - Static
Analysis
Ten Most Critical.
C:CUT-1.PLT
By: CB 05-06-98 1:13pm
Y -Axis
(f t)
0 30 60 90 120 150
PCSTABL5M FSmin=3.08 X -Axis (ft)
Factors Of Safety Calculated By The Modified Bishop Method
1
1
1
t
1
1
PCSTABL5M ••
by
Purdue University
--Slope Stability Analysis --
Simplified Janbu, Simplified Bishop
or Spencer's Method of Slices
Run Date: 05-06-98
Time of Run: 1:16pm
Run By: CB
Input Data Filename: C:CUT-2.IN
Output Filename: C:CUT-2.OUT
Plotted Output Filename: C:CUT-2.PLT
PROBLEM DESCRIPTION Stability of 40 -foot -high, 2:1 cut
slope - Seismic Analysis
BOUNDARY COORDINATES
5 Top Boundaries
5 Total Boundaries
Boundary
X -Left
Y -Left
X -Right
Y -Right
Soil Type
No.
(ft)
(ft)
(ft)
(ft)
Below Bnd
1
.00
20.00
20.00
20.00
1
2
20.00
20.00
60.00
40.00
1
3
60.00
40.00
66.00
40.00
1
4
66.00
40.00
106.00
60.00
1
5
106.00
60.00
150.00
60.00
1
ISOTROPIC SOIL PARAMETERS
1 Type(s) of Soil
Soil Total Saturated Cohesion Friction Pore Pressure Piez.
Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface
No. (pct) (pcf) (psf) (deg) Param. (psf) 140.
1 130.0 130.0 590.0 36.0 .00 .0 0
A Horizontal Earthquake Loading Coefficient
Of .200 Has Been Assigned
A Vertical Earthquake Loading Coefficient
Of .000 Has Been Assigned
Cavitation Pressure = .0 psf
A Critical Failure Surface Searching Method, Using A Random
Technique For Generating Circular Surfaces, Has Been Specified.
200 Trial Surfaces Have Been Generated.
10 Surfaces Initiate From Each Of 20 Points Equally Spaced
Along The Ground Surface Between X = 15.00 ft.
and X = 25.00 ft.
Each Surface Terminates Between X = 110.00 ft.
and X = 130.00 ft.
Unless Further Limitations Were Imposed, The Minimum Elevation
At Which A Surface Extends Is Y = .00 ft.
15.00 ft. Line Segments Define Each Trial Failure Surface.
Safety Factors Are Calculated By The Modified Bishop Method - .
Failure Surface Specified By 10 Coordinate Points
Point
X -Surf
No.
(ft)
1
19.21
2
34.13
3
49.12
4
63.94
5
78.34
6
92.07
7
104.91
8
116.62
9
127.03
10
127.57
Circle Center At X
Y -Surf
(ft)
20.00
18.42
18.78
21.09
25.29
31.33
39.10
48.46
59.27
60.00
38.8 ; Y - 133.6 and Radius, 115.3
*�• 1.994 �.*
Individual data on the 13 slices
Water Water Tie Tie Earthquake
Force Force Force Force Force Surcharge
Slice Width Weight Top Bot Norm Tan Hor Ver Load
No. Ft(m) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kc) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg)
1 .8 4.3 .0 .0 .0 .0 .9 .0 .0
2 14.1 8016.9 .0 .0 .0 .0 1603.4 .0 .0
3 15.0 23809.5 .0 .0 .0 .0 4761.9 .0 .0
4 10.9 24963.4 .0 .0 .0 .0 4992.7 .0 .0
5 3.9 9856.7 .0 .0 .0 .0 1971.3 .0 .0
6 2.1 4973.5 .0 .0 .0 .0 994.7 .0 .0
7 12.3 31443.1 .0 .0 .0 .0 6288.6 .0 .0
8 13.7 38008.3 .0 .0 .0 .0 7601.7 .0 .0
9 12.8 35084.8 .0 .0 .0 .0 7017.0 .0 .0
10 1.1 2870.7 .0 .0 .0 .0 574.1 .0 .0
11 10.6 21798.0 .0 .0 .0 .0 4359.6 .0 .0
12 10.4 8298.4 .0 .0 .0 .0 1659.7 .0 .0
13 .5 25.8 .0 .0 .0 .0 5.2 .0 .0
Stability of 40 -foot -high, 2:1 cut slope - Seismic Analysis
Ten Most Critical. C:CUT-2.PLT By: CB 05-06-98 1:16pm
# FS
a 1.99
Label
b 2.00
Bedrock
c 2.00
d 2.00
e 2.00
f 2.00
9 2.00
h 2.01
1 2.01
1 2.01
I Total Saturated Cohesion Friction Pore Pressure Piez.
e Unit Mt. Unit Mt. Intercept Angle Pressure Constant Surface
%f) %f) tsof cdv Parham. c oft No.
1 f h 4
Y -Axis 60 d
(ft)
0 30 60 90 120
PCSTABL5M FSmin=1.99 X -Axis (ft)
Factors Of Safety Calculated By The Modified Bishop Method
IJV