HomeMy WebLinkAboutParcel Map 30178 Parcel 1-2 Subsurface Soil Report Sept 9 2001ii.
The Legacy Group
43232 Brookway Drive
Temecula, CA 92592
Attention: Mr. Larry Slusser
0 -
1-800-564-7372
(909) 780-0150
FAX 780-8291
September 09, 2001
W.O. 00514
Subject: Subsurface Soils Engineering Investigation for Tentative Parcel Map No.
30178, In the City of Temecula, County of Riverside, California
Gentlemen:
Presented herein, per your request, are the results of our subsurface soils engineering
investigation for two (2) lots known as Tentative parcel Map No 30178, in the City of Temecula,
County of Riverside, California. The property is located contiguous to and easterly of Ormsby
Road (see Figure 1, Site Location Map).
The results of our investigation indicate that the soils underlying the proposed pad areas are
comprised of loose colluvium and alluvium. Pad 2, below loose colluvium is underlain by dense
bedrock. Pad 1 is underlain by dense alluvium at depth.
Based upon our review of site grading plan (Plate 1), it is proposed to grade subject parcel by
standard fill and cut grading techniques into two separate buildable pads for residential
construction. Pad 1 is programmed for 2:1 fill slopes to heights up to 22 feet. Pad 2 is
programmed for both 2:1 fill and cut slopes at 7 feet and 28 feet; respectively. It is our opinion
that the sites should be considered suitable for the planned development, provided the
recommendations presented herein are incorporated into design and in construction. Adequately
constructed spread footings founded into competent, field approved compacted fill, are expected
to provide necessary support for future planned residential structures.
This report has been prepared in accordance with the generally accepted engineering standards
considered necessary for the proposed development. Thank you for the opportunity to be of
service on your project. Should you have any questions regarding this report, please call the
undersigned at your convenience.
Respectfully sutd3r
AM/PAC A d1Y cA toz '
Wade WilihartN No. i i�3 j Stan Schuppcc
CEG 13081r \
RCE 14568, Exp. 3/31
Exp.1/31/03
AM/PAC AN® ASSOCIATES
P.O. Box 545 • Norco, CA 92860
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TABLE OF CONTENTS
SECTION
Site Vicinity Map
1.0
Introduction
1.1
Proposed Development
1.2
Site Description
2.0
Scope of Work
3.0
Site Conditions
3.1
Subsurface Conditions
3.2
Excavatibility
3.3
Groundwater
3A
Subsurface Variations
3.5
Liquefaction
3.6
Potential Seismic Hazards
4.0
Evaluations and Recommendations
4.1
General Evaluations
4.1.1
Preparations for Structural Pad Area
4.1.1.1
Compacted Fill
4.1.2
Non -Engineered Fill
4.2
Spread Foundations
43
Resistance to Lateral Loads
4.5
Construction Considerations
4.5.1 Cut Slopes
4.5.1.1 Unsupported Excavations
4.5.2 Supported Excavations
4.6
Site Preparations
4.7
Soil Caving
4.8
Retaining Wall
4.9
Utility Trench Backfill
4.10
Pre -Construction Meeting
4.11
Seasonal Limitations
4.12
Planters
4.13
Landscape Maintenance
4.14
Observations and Testing During Grading
4.15
Plan Review
5.0
Earthwork/General Grading Recommendations
6.0
Closure
7.0
Appendix Section
Professional Limitation
PAGE 2 AWPAC AND ASSOCIATES
•
W.O. 00514
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. rit Tentative Parcel Map 30178: Page & Grid 979 81
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Tentative Parcel Map Number 30178 • • W.O. 00514
1.0 Introduction
This report presents the results of our subsurface soils engineering investigation for two (2) lots
known as Tentative parcel Map No 30178, in the City of Temecula, County of Riverside,
California. The property is located contiguous to and easterly of Ormsby Road (see Figure 1,
Site Location Map).
The purpose of this evaluation is to determine the nature and engineering properties of the
subsurface soils, and to provide necessary geotechnical recommendations for site grading,
foundation design, slab -on -grade, utility trench backfill, and inspection during construction.
Our evaluation included subsurface exploration, soil sampling, laboratory testing, engineering
analyses and preparation of this report. The recommendations contained herein reflect our
professional opinions for the subsurface soil conditions encountered during,field investigation.
1.1 Proposed Development
Based upon our review of site grading plan (Plate 1, "Tentative Parcel Map No. 30178, prepared
by Alan R. Short, P.E., at a scale of 1 inch equals 20 feet with primary contour intervals of 5 feel
and secondary intervals of 1 foot; undated, it is proposed to develop two buildable pads by
cut/fill grading techniques. For Pad 1, 2:1 fill slopes on the order of 1 to 22 feet are
programmed. For Pad 2, 2:1 fill and cut slopes are programmed for pad development. Cut
slopes on the order of 28 feet, at 2:1 gradients and fill slopes to heights of 7 feet at 2:1 gradients
are programmed for pad 2. For the subject pads, cut materials are to be placed as compacted fill
for lot development (see Plate 1). Earthwork quantities are estimated at 10,000 cubic yards of
cut material and 10,000 cubic yards of fill. (balance).
It is our opinion that the site should be considered suitable for the planned development,
provided the recommendations presented herein are incorporated into design and in construction.
Adequately constructed spread footings founded into competent, field approved certified
compacted fill, are expected to provide necessary support for the planned residential structures.
1.2 Site Description
The property is located north of Santiago Road and east and contiguous to Ormsby Road, City of
Temecula, County of Riverside, California, the property is located within a alluvial area (Pad 1)
and upon a northeasterly -trending spur ridge (Pad 2) which has been previously cut from grading
activities near the ridge top. Natural slope gradients for Pad 1 range from approximately 10:1 to
16:1, with sheet flow drainage to the west and southwest. For Pad 2, gradients range from
approximately 3:1 to 13:1 with compound sheet flow drainage with the western portion draining
to the west and easterly portion draining to the south.
PAGE 4 AM/PAC AND ASSOCIATES
Tentative Parcel Map Number 30178 0 • W.O. 00514
2.0 Scope of Work
Geotechnical investigation for the subject site included subsurface exploration utilizing a truck
mounted Mobile B-34 drill rig, soil sampling, laboratory testing,. engineering analyses and
preparation of this report. In general, scope of work included the following tasks:
o Three exploratory borings were excavated using a truck mounted Mobile B-34
drill rig, advanced to maximum depths of 30 feet below the existing grade (see
Plate 1 & Boring Logs, Appendix Section). During exploration, encountered
subsurface soils were logged based upon visual and tactile methods with bulk
samples obtained at subsurface zones at or near programmed pad grade.
Undisturbed samples were obtained as noted in Boring Logs (Appendix Section).
Collected samples were transferred to our laboratory for testing and analyses.
Descriptions of encountered subsurface soils are provided on the Boring Logs in
Appendix Section. Approximate locations of test borings are shown on Plate 1.
Laboratory testing conducted on selected bulk and in-place samples were
programmed according to the project requirements. The laboratory testing
included determinations of Maximum Dry Density and Optimum Moisture
content, in-place Density/Moisture, soil Shear Strengths and Consolidation
characteristics under anticipated structural loadings. Descriptions of the test
procedures used and test results are provided in Appendix Section.
Based on obtained data resulting from our field investigation, laboratory testing
and engineering analyses, this report presents this firms recommendations for
grading, site preparation, foundation design, slab -on -grade and field review
necessary during site construction.
3.0 Site Conditions
The subject property currently has loose and porous colluvium/alluvium mantling sites to depths
of approximately 4-5 + feet. In addition, loose colluvial soil mantles Pad 2 to approximate
depths up to 5 + feet. Pad 2 has been cut graded in the past, most probably for borrow material
for nearby developments. The property is mantled by light native grass and weed vegetation.
Access to the property is off Ormsby Road via unimproved dirt roads. Drainage is to the
west/southwest for Pad 1 and west and south for Pad 2 via sheet flow.
3.1 Subsurface Conditions
Our evaluation of the site subsoil conditions are based upon subsurface soil exploration and
necessary laboratory testing.
For the depths explored, the encountered 0-5 feet of subsoils primarily consist of loose and
porous colluvial/alluvial soil underlain by bedrock comprised of sandstone. On-site soils are
PAGE 5 AM/PAC AND ASSOCIATES
Tentative Parcel Map Number 30178 • • W.O. 00514
primarily comprised of silty fine to coarse-grained sand, in a dry to slightly moist/moist, loose to
medium dense, dense state.
Based upon field investigation, soil sampling and subsequent laboratory and engineering
analyses, the following characteristics for the site soils are observed:
In general, the upper 0 to 5 + feet of the site soils are loose and compressible. In-place and
underlying earth materials below 5 + feet should be considered to be dense and suitable for
structural support of compacted fill and planned construction (actual approval is dependent upon
field exposure at time ofgrading by project soils engineering consultant/engineering geologist).
At time of construction, actual field exposures will dictate site suitability for depth removals
based upon field review by the project engineering geologist and soils engineering consultant.
Laboratory shear tests conducted on in-place sample and upper bulk samples remolded to 90
percent of the laboratory determined Maximum Dry Density indicate moderate shear strengths
under increased moisture conditions. Results of the laboratory shear tests are provided on Plate
A-1 in Appendix Section.
Consolidation tests conducted on remolded samples indicate low potential for compressibility
under anticipated structural loadings. Results of the laboratory determined soils consolidation
potential are shown on Plate B-1 in Appendix Section.
Due to granular nature of encountered soils, expansion tests (EI) were not conducted as the
encountered subsoils are not considered to be expansive. At time of grading, at finish pad
elevation, surface soils in building foot print should be evaluated for expansion potential.
3.2 Excavatibility
Considering the alluvial/colluvial/friable sandstone nature of the subsoils, it is our opinion that
grading and excavation required for the project may be accomplished using conventional
construction equipment to anticipated programmed depths.
3.3 Groundwater
Encountered subsoils at depths of 30 feet, Boring B-1, were in a moist state. Groundwater was
not encountered during our subsurface drilling excavation to depths up to 30 feet. Groundwater
is not expected to be a problem during grading and construction.
3.4 Subsurface Variations
Based upon the results of our subsurface investigation and on past experience, it is the opinion of
this firm that variations in the continuity, depths of subsoil deposits and bedrock may be
expected. Due to the nature and characteristics of the soils underlying the subject site, care
should be exercised in interpolating or extrapolating the conditions and properties of the subsoils
beyond the boring locations.
PAGE 6 AM/PAC AND ASSOCIATES
_ Tentative Parcel Map Number 30178 •
3.5 Liquefaction
• W.O. 00514
Liquefaction is caused by the build up of excess hydrostatic pressure in saturated cohesionless
soils due to cyclic stress generated by ground shaking during an earthquake. The significant
factors on which liquefaction potential of a soil deposit depends, among others include, soil type,
relative soil density, intensity of earthquake, duration of ground shaking, and depth of ground
water.
Ground water was not encountered in our subsurface exploration program to explored depths.
Earth materials underlying Pad 1 consist of dense alluvial silty to clayey fine to coarse-grained
sand. Pad 1 is expected to expose dense silty fine to coarse-grained sand in a dense state. It is
the opinion of this office, that Pad 1 is not subject to the effects of liquefaction, based upon
absence of ground water to explored depths.
Due to absence of ground water to explored depths and the fact that underlying in-place bedrock
materials below Pad 2 consists of dense sandstone bedrock. It is the opinion of this firm that the
potential for liquefaction does not exist for Pad 2.
3.6 Potential Seismic Hazards
Seismic Design Parameters Based upon 1997 UBC
The seismic design fault for the subject property is the Elsinore Fault, Glen Ivy segment, which
is located within 2 kilometers westerly/southwesterly of the subject property. The fault type is
"B." The maximum magnitude is noted by the UBC as 6.8. The slip rate is 5 mm/yr. The
Near -Source Factor N., is noted as 1.3; the Near -Source Factor N, is noted as 1.6.
The soil materials underlying the subject site is assigned the Soil Type Profile Sp. The Seismic
Zone Factor is 0.40. The Seismic Coefficient, C„ is noted as 0.44N,;the Seismic Coefficient, C,,
is noted as 0.64N,.
4.0 Evaluations and Recommendations
4.1 General Evaluations
Based on this firm's field investigation, laboratory testing and subsequent engineering analysis, it
is our opinion that, from a geotechnical viewpoint, the site should be considered suitable for the
planned development, provided the recommendations presented herein, are incorporated into
final design and in construction.
Based upon grading plan review, it is proposed to cut and fill existing grades to programmed pad
grades of 1138 and 1160 for Pads 1 & 2, respectively. After removal of upper loose and porous
soils (subject to field exposures and approval by the project soils engineering consultant and/or
engineering geologist), suitable bearing native earth materials should be exposed for support of
intended fill sections. If suitable bearing native materials are not exposed, additional removals
PAGE 7 AM/PAC AND ASSOCIATES
Tentative Parcel Map Number 30178 • • W.O. 00514
will be required. Cut areas within building pad should be overexcavated to suitable bearing soil
depths and brought back to design grade with compacted fill. Cut slopes should be field
evaluated by the project engineering geologist. Should unsuitable loose materials and or adverse
planar conditions be exposed, cut slopes may require replacement with a drained stabilization fill
section.
Programmed structural fill areas will be founded upon in-place field approved, by project
engineering geologist or soils engineering consultant), competent earth materials.
Site preparation and grading should be performed in accordance with the enclosed
recommendations of Section 5, Earthwork/General Grading Recommendations of this report,
except as modified in the main text and with the applicable portions of Appendix Chapter 33 of
the current UBC or applicable local ordinance.
Structural design considerations should include the probability of moderate to high peak ground
accelerations from relatively active nearby earthquake faults as noted in Section 3.6.
4.1.1 SubGrade Preparations for Fill and Structural Pad Area
Project soils engineering consultant and/or engineering geologist should review removal of
unsuitable soil materials to competent structural earth materials. Fill should be placed under the
observation and testing of the project soils engineering consultant. Due to the potential for
differential settlement from founding building footings on cut and fill materials, it is
recommended that the building area and five feet beyond (including fill transition area), should
be overexcavated to a minimum depth of five (5) + feet below finish grade to provide for
uniform bearing of foundation area. Actual depth of removal is dependent upon exposure of
dense native earth materials as approved by the project soils engineering consultant and/or
engineering geologist. Following excavation, the bottom exposure should be further scarified to
6 -inches, moisture conditioned and recompacted to a higher density (90%) prior to new fill
placement. Fill blanket placed should be compacted to at least 90 percent of the Maximum Dry
Density as determined by the laboratory standard ASTM D1557-91 test standard. General
earthwork recommendations are enclosed with this report.
4.1.1.1 Compacted Fill Slope
For adequate structural fill support, programmed fill slope areas should be grubbed and cleared
of deleterious debris and organics. Prior to fill placement, a keyway should be constructed,
equipment width (minimum of 15 feet) with the toe and heel founded 1 and 2 feet, respectively,
below competent approved earth materials (due to loose surface soils, minimum depth is
expected to be 4-5 + feet. Keyway is to be field approved by this office. Fill placement against
slopes steeper than five to one should be benched through all unsuitable topsoil, colluvium,
alluvium, or creep materials into sound bedrock or firm earth material in accordance with the
recommendations and approval of the project engineering geologist and/or soils engineering
consultant. Depending upon exposed field conditions, localized back drains may be required
behind slope fill sections at the natural ground contact, especially in areas where natural swale
contours are located. Actual need and recommendations will be dependent upon exposed field
PAGE 8 AM/PAC AND ASSOCIATES
_ Tentative Parcel Map Number 30178 • • W.O. 00514
r conditions and upon recommendations of the field reviewing engineering geologist/soils
engineering consultant.
4.1.2 Non -Engineered Fills
It is the understanding of this office that all fill placed will be engineered structural fill.
4.2 Spread Foundations
For adequate support, the proposed structures may be constructed on continuous and/or isolated
spread footings founded exclusively into field approved, dense alluvial materials.
Conventional shallow foundation system is considered suitable for planned residential and
ancillary structures. Type Il cement is considered suitable for subject project (Sulfate content is
negligible less than 100 ppm).
Foundations may be designed based upon the following values:
Allowable Bearing: 1800 lbs./sq.ft.
Lateral Bearing: 250 lbs./sq.ft. per foot of depth to a maximum of 1500 lbs./sq.ft.
Sliding Coefficient: 0.25
The above values may be increased as allowed by Code to resist transient loads such as wind or
seismic. Building code and structural design considerations may govern depth and reinforcement
requirements and should be evaluated.
2. Other Design Recommendations
* FOOTING DEPTH
Exterior
Interior
* FOOTING Width
Exterior
Interior
* FOOTING REINFORCEMENT
Exterior & Interior -
Concrete Slabs
12 -inches below lowest adjacent grade (in approved
dense compacted fill materials) for one story
and 18 -inches below adjacent grade (in approved
dense compacted fill materials) for 2 -story.
12 -18 -inches below lowest adjacent grade (in
approved dense compacted fill materials) for one and
2 -story, respectively.
12 inches for one-story and 15 inches for 2 -story.
12 inches for one-story and 15 inches for 2 -story.
All continuous; four No. 4 bars, two near the top,
two near the bottom for exterior and two No. 4
bars, one near the top and one near the bottom for
the interior.
The prepared subgrade to receive foundations should be
-- --considered adequate for concrete slab -on -grade. - For normal
PAGE 9 AM/PAC AND ASSOCIATES
Tentative Parcel Map Number 30178 • • W.O. 00514
load bearing conditions, 4 -inch thick (net) concrete slabs
reinforced with 6 -inch x 6 -inch No. 6 X No. 6 WWF is
recommended. Reinforcement should be installed at
mid -height in the slab.
* Under -Slab Treatment
Living Areas- 6 -mil Visqueen; cover with at least 2 inches of sand.
Subgrade soils should be pre -moistened to contain at
least optimum moisture content immediately prior
to placing Visqueen and to be verified by the soils
engineering consultant. The sand cover should be
moistened prior to placing concrete.
Grade Beam - A grade beam reinforced continuously with the
garage footings should be constructed across all
garage entrances, tying together the ends of the
garage footings. This grade beam should be
embedded at the same depth as the adjacent
perimeter footings
Garaee Slab - Optimum moisture content in subgrade soil verified
by the soils engineering consultant.
* Fireplace Footings - Fireplace footings shall have a minimum
embeddment depth of 12 -inches measured from the
lowest adjacent grade and should be an integral part
of the building foundation system. Fireplace slabs
shall be treated in the same manner as the living
area slabs (same as that noted in following sections
for slab -on -grade construction).
*Prior to pouring footings, soils should be pre -moistened and field approved by the project soils engineering
consultant or his representative.
The settlement of properly designed and constructed foundations supported on approved earth materials, carrying
maximum anticipated vertical loadings, are expected to be within tolerable limits. Estimated total and differential
settlements are about 3/4 and 1/2 -inch, respectively.
4.3 Resistance to Lateral Loads
Resistance to lateral loads can be restrained by friction acting at the base of foundations and by
passive earth pressure. A coefficient of friction of 0.25 may be assumed with the normal dead
load forces for footing established on compacted fill. An allowable passive lateral earth
resistance of 250 pounds per square foot per foot of depth, may be assumed for the sides of
foundations poured against compacted fill. However, the maximum lateral passive earth pressure
is recommended not to exceed 1500 pounds. For design, lateral earth pressures of local soils
when used as level backfill may be estimated from the following equivalent fluid density:
PAGE 10
Active: 40 pcf
Passive: 250 pcf
At Rest: 50 pcf
AM/PAC AND ASSOCIATES
Tentative Parcel Map Number 30178 • • W.O. 00514
4.5 Construction Considerations
4.5.1 Cut slopes
Due to the possible presence of loose colluvial/alluvial soils being exposed in finish cut slopes,
slopes exposing these materials will requirement stabilization with a drained stabilization fill
section. All cut slopes are to be field evaluated by the project engineering geologist. Should
slopes require stabilization the following applies: Affected section should have a backcut made
from top of slope to toe which allows for a minimum 15 feet in width keyway with a 10 feet in
width top section. Keyway should be founded 1 and 2 feet, toe and heel, respectively, into
competent approved earth materials. All backcuts are to be mapped by the project engineering
geologist. Backdrains, will be required at the heel elevation and as specified by the geotechnical
consultant based upon exposed field conditions.
All cut slopes are to be field evaluated by the project engineering geologist for structural
documentation. Adverse geology is to be stabilized by means of a stabilization section or if
daylighted planar conditions are encountered, by a designed buttress.
4.5.1.1 Unsupported Excavation
Temporary construction excavation up to a maximum depth of 5 feet may be made without any
lateral support. It is recommended that no surcharge loads such as construction equipment, be
allowed within a line drawn upward at 45 degree from the toe of excavation. Use of sloping for
deep excavation may be applicable where plan dimensions of the excavation are not constrained
by any existing structure.
4.5.2 Supported Excavations
If vertical excavations exceeding 5 feet in depths become warranted, such should be achieved
using shoring to support side walls.
4.6 Site Preparation
Site preparations should include cut subexcavations, import soils, and placement of soils as
engineered fill. Such earth work should be in accordance with the applicable grading
recommendations provided in the current UBC and as recommended in Section 5.0 of this report.
Project soils engineering consultant should be notified 72 hours in advance of importing soils to
site for placement as compacted fill. It will be necessary for the project soils engineering
consultant to sample import soils with subsequent laboratory testing to determine suitability of
import soils for project construction. It is strongly recommended that import soils be similar to
site soils. The use of clayey soils for pad construction is not recommended.
4.7 Soil Caving
During excavations for deep utility trenches, 'some' caving may be expected. All temporary
excavations should be made at a 2:1 (horizontal to vertical) slope ratio or flatter, and/or as per the
construction guidelines provided by CalOSHA----------- -
PAGE 11 AM/PAC AND ASSOCIATES
.. Tentative Parcel Map Number 30178 • W.O. 00514
4.8 Retaining Wall
Retaining structures, if planned, should be designed using the following equivalent fluid density:
Slope Surface of
Equivalent Fluid Density (pcf)
Retained Material
Imported
Local
(horz. to vert.)
Clean Sand
Site Soil
Level
30
40
2:1
35
50
Only free -draining granular materials (sand or gravel) as retaining wall backfill. Backdrains will
be required behind all retaining walls.
4.9 Utility Trench Backfill
Utility trench backfill within the structural pad and beyond, should be placed in accordance with
the following recommendations:
o Trench backfill should be placed in thin lifts compacted to 90 percent or better of the
laboratory maximum dry density for the soils used. As an alternative, clean granular
sand may be used having a SE value greater than 30. Such materials may be jetted or
flooded in place provided provisions are made to release excess water from behind the
wall.
Exterior trenches along a foundation or a toe of a slope and extending below al: I
imaginary line projected from the outside bottom edge of the footing or toe of the
slope, should be compacted to a minimum 90 percent.
o All excavated trenches should conform to the requirements and safety as specified by
the CalOSHA
4.10 Pre -Construction Meeting
It is recommended that no clearing of the site or any grading operation be performed without
the presence of a representative of this office. An on-site pregrading meeting should be arranged
between the soils engineering consultant and the grading contractor prior to any construction.
4.11 Seasonal Limitations
No structural fill shall be placed, spread or rolled during unfavorable weather conditions. Where
the work is interrupted by heavy rains, fill operations shall not be resumed until moisture
conditions are considered favorable by the soils engineering consultant.
PAGE 12 AM/PAC AND ASSOCIATES
Tentative Parcel Map Number 30178 • • W.O. 00514
4.12 Planters
To minimize potential differential settlement to foundations due to migrating subsurface water,
plants requiring heavy irrigation should be restricted from using adjacent to footings. If
unavoidable, planter boxes with sealed bottoms with drains which drain away from foundations,
should be implemented. A qualified landscape architect should be contacted for specific design
recommendations.
4.13 Landscape Maintenance
Only the amount of irrigation necessary to sustain plant life should be provided. Pad drainage
should be directed towards streets and to other approved areas away from foundations. Slope
areas, when applicable, should be planted with draught resistant native type vegetation.
4.14 Observations and Testing During Construction
Recommendations provided in this report are based upon the assumption that all foundations will
be placed on approved compacted fill soils for structure. Excavated footings should be
inspected, verified and certified by soils engineering consultant prior to steel and concrete
placement to ensure their sufficient embeddment and proper bearing on approved engineered fill.
Additional inspections by soils engineering consultant and/or engineering geologist is
recommended to verify footing excavations being free of loose and disturbed material. All
structural backfill should be placed and compacted under direct observation and testing by this
facility. Excess soils generated from footing excavations should be removed from pad areas and
such should not be allowed on subgrades as uncompacted fill prepared to receive concrete
slab -on -grade.
4.15 Plan Review
The recommendations presented herein should be considered 'preliminary'. It is recommended
that if grading plans change, new plans should be presented to this office for review to minimize
misunderstandings between the plans and recommendations presented. Further, excavated
footings should be verified as recommended earlier. If during construction, conditions are
observed to be different from those as described in this report, revised and/or updated
recommendations will be required.
5.0 Earth Work/General Grading Recommendations
Structural Backfill:
During grading, excavated site soils should be considered suitable for reuse as backfill material.
Loose soils, formwork and debris should be removed prior to backfilling the walls. On-site sand
backfill should be placed and compacted in accordance with the recommended specifications
provided below. Where space limitations do not allow conventional backfilling operations,
special backfill materials and procedures may be required. Pea gravel or other select backfill can
PAGE 13 AM/PAC AND ASSOCIATES
Tentative Parcel Map Number 30178 • • W.O. 00514
be used in limited space areas. Recommendations for placement and densification of pea gravel
or other special backfill can be provided during construction.
Site Drainage:
Adequate positive drainage should be provided away from the structure to prevent water from
ponding and to reduce percolation of water into backfill. A desirable slope for surface drainage
is 2 percent in landscape areas and 1 percent in paved areas. Planters and landscaped areas
adjacent to building perimeter should be designed to minimize water filtration into subsoils.
Consideration should be given to the use of closed planter bottoms, concrete slabs and perimeter
subdrains where applicable.
Utility Trenches:
Buried utility conduits should be bedded and backfilled around the conduit in accordance with
the project specifications. Where conduit underlies concrete slab -on -grade and pavement, the
remaining trench backfill above the pipe should be placed and compacted in accordance with the
following grading specifications.
General Grading Recommendations:
Recommended general specifications for surface preparation to receive fill and compaction for
structural and utility trench backfill and others, are presented below.
1. Areas to be graded, backfilled or paved, shall be grubbed, stripped and cleaned of all buried
and undetected debris, structures, concrete, vegetation and other deleterious materials prior to
grading.
2. Where compacted fill is to provide vertical support for foundations, all loose, soft and other
incompetent soils should be removed to depths as approved by soils engineering consultant,
or at least up to the depth as previously described in this report (all removal depths for fill
placement require field approval by the project soils engineering consultant and/or engineering
consultant). The areas of such removal should extend at least 5 feet beyond the perimeter of
exterior foundation limit or to the extent as approved by soils engineering consultant during
grading.
3. The recommended compaction for fill to support foundations and slab -on -grade is 90% of
the Maximum Dry Density at or near Optimum Moisture content. To minimize any potential
differential settlement for foundations and slab -on -grade straddling over cut and fill, the cut
portion should be overexcavated a minimum of 3.0 feet from surface grade and/or as field
approved by the soils engineering consultant and replaced as compacted fill, compacted to at
least 90% of the maximum dry density as described in this report.
4. Utility trenches within building pad areas and beyond, should be backfilled with granular
material and such should be compacted to at least 90% of the maximum density for the material
used.
PAGE 14 AM/PAC AND ASSOCIATES
Tentative Parcel Map Number 30178 • • W.O. 00514
5. Compaction for all structural fills shall be determined relative to the maximum dry density
as determined by ASTM D1557-90 compaction methods. All in-situ field density of compacted
fill shall be determined by the ASTM D1556 standard methods or by other approved
procedures.
6. All fill slopes are to be overfilled a minimum of 5 feet horizontally and cut back to expose a
dense finish slope surface. In lieu of overfilling the slope face, the slope face, if constructed on
grade, should be backrolled with a sheepsfoot roller at 4 feet intervals (vertical). Finish slope
should be grid rolled. Optimum moisture must be maintained on slope face until compaction has
been achieved and approved by the project soils engineering consultant.
7. All new imported soils, if required, shall be clean, granular, non -expansive material or as
approved by the soils engineering consultant.
8. During grading, fill soils shall be placed as thin layers, thickness of which following
compaction shall not exceed six inches.
9. No rocks over eight inches in diameter, shall be permitted to use as a grading material
without prior approval of the soils engineering consultant.
10. No jetting and/or water tampering be considered for backfill compaction for utility trenches
without prior approval of the soils engineering consultant. For such backfill, hand tampering
with fill layers of 8 to 12 inches in thickness, or as approved by the soils engineering consultant
is recommended.
11. Any and all utility trenches at depth as well as cesspool and abandoned septic tanks within
building pad area and beyond, should either be completely excavated and removed from the site.
or should be backfilled with gravel, slurry or by other material, as approved by soils engineering
consultant.
12. Any and all import soils if required during grading, should be equivalent to the site soils or
better. Such should be approved by the soils engineering consultant prior to their use.
13. Any and all grading required for pavement, sidewalk or other facilities to be used by general
public, should be constructed under direct observation of soils engineering consultant, or as
required by the local public agencies.
14. A site meeting should be held between grading contractor and soils engineering consultant
prior to actual construction. Three days of prior notice is recommended for meetings.
PAGE 15 AM/PAC AND ASSOCIATES
Tentative Parcel Map Number 30175 • • W.O. 00514
6.0 Closure
The conclusions and recommendations contained herein, are based on the findings and
observations made at the time of the subsurface investigation. The recommendations presented,
should be considered "preliminary" since they are based on soil samples only. If during
construction, the subsoil conditions appear to be different from those disclosed during field
investigation, this office should be notified to consider any possible need for modification for
the geotechnical recommendations provided in this report.
Recommendations provided are based on the assumptions that structural footings will be
established exclusively into approved engineered fill.
It is required that final "precise grading (ifgrading plan is different than that review for this
report) and foundation plans" should be reviewed by this office when they become available.
Site grading must be performed under field review by geotechnical representatives of this office.
All footing excavations should be field reviewed prior to forming, steel and concrete placement
to ensure that foundations are founded into satisfactory soils and excavations are free of loose
and disturbed materials.
A pregrading meeting between grading contractor and soils engineering consultant should be
arranged, preferably at the site, to discuss the grading procedures to be implemented and other
requirements described in this report to be fulfilled.
This report has been prepared exclusively for the use of the addressee for the project referenced
in context. It shall not be transferred or be used by other parties without written consent by
AM/PAC AND ASSOCIATES. We cannot be responsible for use of this report by others
without inspection of the grading operation by our personnel.
Should the project be delayed beyond one year after the date of this report, the
recommendations presented shall be reviewed to consider any possible change in site conditions.
The recommendations presented are based on the assumption that the necessary geotechnical
observations and testing during construction will be performed by a representative of this office.
The field observations are considered a continuation of the geotechnical investigation performed.
If another firm is retained for geotechnical observations and testing, our professional liability and
responsibility shall be limited to the extent that AM/PAC AND ASSOCIATES would not be the
geotechnical engineer of record.
PAGE 16 AM/PAC AND ASSOCIATES
Tentative Parcel Map Number 30178 • • W.O. 00514
7.0 APPENDIX Section
Field Exploration
The field investigation for the project included site reconnaissance and subsurface exploration
using a truck mounted drill rig. During the site reconnaissance, the surface conditions were noted
and test boring locations were determined. Soils encountered during explorations were
continuously logged and such were classified by visual observations and tactile methods in
accordance with generally accepted field classification. The field descriptions were modified,
where appropriate, to reflect laboratory test results.
Undisturbed ring soil samples were obtained. Where appropriate, representative bulk soil
samples were also obtained.
Logs of the test explorations are presented in the following summary sheets, that include the
description of the soils and/or bedrock materials encountered.
PAGE 17 AM/PAC AND ASSOCIATES
Tentative Parcel Map Number 30178 • • W.O. 00514
Boring Logs
PAGE 18 AM/PAC AND ASSOCIATES
0 0
AM/PAC And ASSOCIATES
Log of Boring No. B-1
Date Observed: 8/16/01 Method of Drilling: Flight Auger
Logged by: LWW Ground Elevation 1133
W.O.00514
Depth
ft.
Sample
Blows
7i.
Group
Syb.
Unit dry wt.
Qba. caftJmoist.
%
Description and Remarks
1
Bulk
0-5'
Drive
Drive
25
SWSW
sw
SW
SUG`
SW
126.3
114.6
8.3
8.7
0-3' Alluvium (Qal): Silty fine to medium -grained sand, It. brown,
dry, loose, porous no sample recovery
Silty fine to coarse-grained sand, brown, moist, medium dense to
dense
Silty fine to very coarse-grained sand, brn, moist, dense
Clayey silty fine-grained sand/sandy clay, bm, moist, dense
Silty fine to medium -grained sand, brit, moist, dense
2
3
4
5
6
7
8
9
10
I1
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
0
AM/PAC And ASSOCIATES
Log of Boring No. B-1
Date Observed: 8/16/01 Method of Drilling: Flight Auger
Logged by: LWW Ground Elevation 1133 W.O.00514
28
E.O.B. @ 30 ft.
No Water No Caving
29
30
0 0
AM/PAC And ASSOCIATES
Log of Boring No. B-2
Date Observed: 8/16/01 Method of Drilling: Flight Auger
Logged by: LWW Ground Elevation 1144 W.O.00514
Depth
n
s..'i'
Blo"
n.
o'°°'
syn
"""°"
on,. a n i
%
moist.
Description and Remarks
p
]
Drive
22
sw
Colluvium (Qcol): Silty fine to medium -grained sand, It. brown, dry,
loose
Very fine to medium -grained sand, It. bm, moist, medium dense
to dense; scattered subrounded pebbles; no sample recovery
Very fine to coarse-grained sand, brown, moist, dense; scattered
subrounded pebbles
Medium to coarse-grained sand, brown, very moist, dense
E.O.B. @ 15 ft.
No Water No Caving-
aving21
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
0 0
AM/PAC And ASSOCIATES
Log of Boring No. B-3
Date Observed: 8/16/01 Method of Drilling: Flight Auger
Logged by: LWW Ground Elevation 1167 W.O.00514
De'p,b
fi.
Sample
Blown
O.
Group
Syb,
Uni,dryw,.
Qba.. A
%
ff10151.
Description and Remarks
P
]
Drive
Bulk
31
sw
116.3
129.4
7.6
9.2
Colluvium (Qcol): Very fine-grained sand, brown, dry, loose
Bedrock: Silty fine to coarse-grained sand, bm, moist, dense
scattered subrounded pebbles; no sample recovery
Fine to coarse-grained sand, bm, moist, dense; scattered subrounded
pebbles
Fine to very coarse-grained sand, It. tan bm, moist, dense; scattered
subrounded pebbles
E.O.B. @ 19 ft.
No Water No Caving
2
3
4
5
6
7
8
9
10
] ]
12
13
14
] 5
16
17
18
19
20
21
22
23
24
25
Tentative Parcel Map Number 30178 • • W.O. 00514
8.0 APPENDIX B
Laboratory Test Programs
Laboratory tests were conducted on representative soils for the purpose of classification and for the determination
of the physical properties and engineering characteristics. The number and selection of the types of testing for a
given study are based on the geotechnical conditions of the site. A summary of the various laboratory tests
performed for the project is presented below.
Moisture Content ASTM D4643 and Dry Density
Data obtained from these tests, performed on relatively undisturbed soil samples, were used to aid in the
classification and correlation of the soils. The test results are provided in the Boring log.
Direct Shear (ASTM D 3080)
Data obtained from this test performed at increased moisture conditions on remolded soil samples was used to
evaluate soil shear strengths. Samples contained in brass sampler rings, placed directly on test apparatus are
sheared at a constant strain rate under a normal load, appropriate to represent anticipated structural loadings.
Shearing deformations are recorded to failure. Peak and/or residual shear strengths are obtained from the
measured shearing load versus deflection curve. Test results, plotted on graphical form, are presented on Plate A -I
of this section.
Consolidation (ASTM D2435)
Data obtained from this test performed from remolded samples, were used to evaluate the consolidation
characteristics of foundation soils under anticipated foundation loadings. Preparation for this test involved
trimming the sample, placing it in one inch high brass ring, and loading it into the test apparatus which contained
porous stones to accommodate drainage during testing. Normal axial loads are applied at a load increment
ratio, successive loads being generally twice the preceding.
Soil samples are usually under light normal load conditions to accommodate seating of the apparatus. Samples
were tested at the field moisture conditions at a predetermined normal load. Potentially moisture sensitive soil
typically demonstrate significant volume change with the introduction of free water. The results of the
consolidation tests are presented in graphical forms on Plate B-1.
Potential Expansion
Due to granular nature of site soils, no expansion testing was conducted as the soils are considered to be non
expansive. At final grade expansion characteristics should be verified by laboratory testing.
Laboratory Test Results
Maximum Dry Density/Optimum Moisture Content Relationship
(ASTM D1557-91)
Sample Location
Max. Dry Density (pcf)
Opt. Moisture Content (%)
B- 1, 0-5 feet
126.3
8.3
B-3, 5-10 feet
129.4
9.2
PAGE 19 AM/PAC AND ASSOCIATES
DIRECT' SHEAR TESTS
in
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V
Z
o
C
V
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�7
Nin
O
O
0 0.5 LO L5 ZO 2.5
NORMAL LOAD - YIPS PER SQUARE FOOT
SYMBOL LOCATION DEPTH (ft) TEST CONDITION COHESION FRICTION
A B-1 BulkRemold (psi) (degrees)
0.0-5.0' Saturated & Drained 40 33
City of Temecula, California PROJECT NO. 00514
AM/PAC AND ASSOCIATES-
P.O. BOX 545, NORCO, CA 92860 PLATE A-1
• Tentative Parcel Map Number 30178 • • W.G. 00514
PROFESSIONAL LIMITATIONS
Our investigation was performed using the degree of care and skill ordinarily exercised, under similar circumstances
by other reputable Soils Engineers practicing in this general or similar localities. No other warranty, expressed or
implied, is made as to the conclusions and professional advise included in this report. .
The investigations are based on soil samples only, consequently the recommendations provided shall be considered
'preliminary'. The samples taken and used for testing and the observations made are believed representative of site
conditions; however, soil and geologic conditions can vary significantly between borings. As in most major
projects, conditions revealed by excavations may vary with preliminary findings. If this occurs, the changed
conditions must be evaluated by the Project Soils engineering consultant and designs adjusted as required or
altemate design recommended.
The report is issued with the understanding that it is the responsibility of the owner, or of his representative, to
ensure that the information and recommendations contained herein are brought to the attention of the project
architect and engineers. Appropriate recommendations should be incorporated into structural plans. The necessary
steps should be taken to see that the contractor and subcontractors carry out such recommendations in field.
The findings of this report are valid as of this present date. However, changes in the conditions of a property can
occur with the passage of time, whether they due to natural process or the works of man on this or adjacent
properties. In addition, changes in applicable or appropriate standards may occur from legislation or broadening of
knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by change outside of our
control. Therefore, this report is subject to review and should be updated after a period of one year.
RECOMMENDED SERVICES
The review of grading plans and specifications, field observations and testing by the geotechnical representative is
an integral part of the conclusions and recommendations made in this report. If AM/PAC AND ASSOCIATES
ENGINEERING is not retained for these services, the Client agrees to assume AM/PAC AND ASSOCIATES
ENGINEERING responsibility for any potential claims that may arise during and after construction, or during the
lifetime use of the structure and its appurtenant. The required tests, observations and consultation by the
geotechnical consultant during construction includes, but not be limited to:
a. Continuous observation and testing during site preparation and grading, and placement of engineered fill.
b. Observation and inspection of footing trench prior to steel and concrete placement,
c. Geologic cut slope evaluation and keyway approval for fill slopes.
d. Geologic vertical cuts in native earth materials for retaining walls should be evaluated by the project geologist
e. Consultations as required during construction, or upon your request.
PAGE 20 AM/PAC AND ASSOCIATES
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