HomeMy WebLinkAboutAsBuiltGeology&FinalCompactionRoughGrading(Jun.5,1991)~~~ ~1 .~ ;~ti~.
AS-RSJiYt~'~GE4~OGY AND
FINAL C~El~~il~l~l~'~PdRI~ ~OF ROUGH
GRADING
Tracts 24131, 24131-1,24131-2, -24131-~ and a
Portion of 24186
Paloma Del Sol
Master Plan Community
Temecula, California
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Converse Consultants
Inland Empire
70397 Corporate Drive
Redlands, CA 92374
Telephone 909 / 796-054a
FAX 909 796-7675
AS-BUILT GEOLOGY AND
FINAL COMPACTION REPORT OF ROUGH
GRADING
Tracts 24131, 24131-1,24131-2, 24131-3 and a
Portion of 24186
Paloma Del Sol
Master Plan Community
Temecula, California
Conducted for:
Mesa Homes
28765 Single Oak Drive
Suite 100
Temecula, California
CCIE Project No. 88-81-148-03
June 5, 1991
Consulting Engineering
anA Applied Sciences
AWhollyOwnedSubsidiaryof !~
The Converse Pmfessional Graup
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,`~
June 5, 1991
Converse Consultants
Inland Empire
Consulting Engineering
and Applied Sciences
10397 Corporete Drive
Redlands, CA 92374
Telephone 909/796-054a
FAX 909 796-7675
Mesa Homes
28765 Single Oak Drive, Suite 100
Temecula, California 92390-0295
Attn: Mr. Csaba F. Ko
Subject: AS-BUILT GEOLOGY AND FINAL COMPACTION
REPORT OF ROUGH GRADING TRACTS 24131,
24131-1, 24131-2, 24131-3 and a Portion of 24186
Paloma Del Sol Master Planned Community,
City of Temecula, California
CCIE Project No. 88-81-148-03
Converse Consultants inland Empire (CCIE) prepared this report containing results of
geologic mapping, laboratory analysis and field density testing performed during rough
grading of the subject site.
The approximate locations of field density tests and geologic mapping are shown on
Drawings 1 through 9 of the 1"=40' scale, rough grading plan, prepared by Robert
Bein, William Frost & Associates of Rancho California, California.
Based on the results of our geologic observations and fieid density testing, it is our
opinion that the earthwork associated with the grading of the site has been performed
in accordance with sound geologic and soil engineering practices.
We appreciate the opportunity to be of service to you. If you have any further
questions, or need further assistance, please do not hesitate to call us.
Very Truly Yours,
CONVERSE CONSULTANTS INLAND EMPIRE
~ ~
Steven C. Helfri
Principal Engineer/Br ch Manager
Dist: 8/Addressee
AWhollyOwnedSubsitliaryof ~
Tha Conversa Profeuional Group
~ - `;
PROFESSIONAL CERTIFICATION
This report has been prepared by the staff of Converse Consultants Inland Empire
under the professional supervision of the Principal Engineer and Senior Engineering
Geologist whose seals and signatures appear hereon.
The findings, conclusions, recommendations, or professionai opinions presented in this
report were prepared in accordance with generally accepted professional engineering
~ractice. There is no other warranty, either expressed or implied.
Steven C. Helfrich, G 389
Principal En i
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Senior Geologist
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TABLE OF CONTENTS
SUMMARY OF WORK PERFORMED . . . . . . _ . . . . . . . . . . . . . . . . . . . 1
General .........................................1
RoughGrading .................................... 1
MOISTURE CONDITIONING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
GEOLOGIC CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Earth Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Fill ..........................................4
Pauba Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Faults Exposed During Grading . . . . . . . . . . . . . . . . . . . . . . . . . 4
Slopes ..........................................4
Groundwater Seepage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
CONCLUSIONS ........................................5
RECOMMENDATIONS .................................... 8
Foundation Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Post-tensioned Slabs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Pre-Soaked Building Pads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Slabs-on-Grade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Lateral Earth Pressures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Preliminary Pavement Design . . . . . . . . . . . . . . . . . . . . . . . . . 10
Site Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Slope Protection and Maintenance . . . . . . . . . . . . . . . . . . . . . . 13
On-site Trench Backfill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Continuing Observation and Testing Services . . . . . . . . . . . . . . 1.4
LIMITATIONS ........................................ 15
REFERENCES ......................................... 16
Figure No. 1 - LOCATION OF GRADING . . . . . . . . . . . . . . . . . . . . . . . . 2
Figure No. 2 - HISTOGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Table No. 1 - LOT CLASSIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Table No. 2 - FOUNDATION RECOMMENDATIONS . . . . . . . . . . . . . . . . 9
Table No. 3 - ASPHALT PAVEMENT SECTIONS . . . . . . . . . . . . . . . . . 12
APPENDIX A- Laboratory Test Data
APPENDIX B- Summary of Field Density Tests
TEST LOCATION AND GEOLOGIC MAPS -(40 scale) - in pocket (9 sheetsl
88-81-148-03
s
Convsrsa Consuk~nt~ Inland Empiro
SUMMARY OF WORK PERFORMED
n r I
This report covers Tracts 24131, 24131-1, 24131-2, 24131-3 and a portion of
24186. Earthwork was performed by E.L. Yeager Construction, Inc., of Riverside,
California. During April 12, 1990 through November 28, 1990, observations and
testing were conducted by CCIE at the subject sites. Accepted engineering and
testing procedures were employed to evaluate the preparation of the natural ground
surface and placement and compaction of the fill.
Rough Gradin9
Rough grading for the subject sites was performed in accordance with the
"Geotechnical Investigation" report dated December 23, 1988 and the earthwork
specifications at the location shown on Figure 1, "Location of Grading".
Canyons exposing unsuitabie alluvial/colluvial soils were excavated. The exposed
excavated surface was then scarified, brought to near optimum moisture content and
compacted prior to placement of excavated soils as fills.
Fills were placed in loose, 6 to 8 inch thick lifts. Fill materials were brought to near
optimum moisture and mixed by an 824 dozer pulling a bee gee. Rough grading was
accomplished by Caterpiiler 633, 651 and 657 scrapers, 10,000 gal. water pulls and
824 dozers. Motor graders were utilized to fine grade lots.
After clean out, and prior to filling the canyons, the canyon subgrade was observed
by a certified engineering geologist. It was observed that the canyon bottoms
contained clean sands. Accordingly, canyon subdrains were not considered necessary
due to the free draining characteristics of the subgrade.
Where fiils were placed against existing slopes steeper than 5:1 (horizontal:vertical~,
the existing slopes were keyed and benched to provide a series of approximately level
benches to seat the fill and remove the compressible colluvial soils.
Where lots indicated a cut/fiil transition at finish pad elevation, the lots were
overexcavated a minimum of three feet below finai lot grade. The bottom was then
scarified, brought to near optimum and compacted prior to placing fill.
Fill slopes were overfilled 3 to 4 feet and compacted as they were filled horizontally
with the fully loaded heavy equipment. The overfilled slope face was then track rolled
with the D-8 and D-9 dozers. The slope face was then trimmed back to grade by the
D-8 dozer equipped with a slope board.
88-81-148-03
Conv+na Canwkanb In1~M Empiro
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LOCATION OF GRADING
PALOMA DEL SOL MASTER PLAN COMMUNITY v,o,eano.
Temecula, California 88-81-148-0:
for: Mesa Homes
Frg~re NO.
~-~ Converse Consultants Inland Empire ~
The laboratory maximum dry density was determined in accordance with the ASTM
D1557-78 (five tayer) method. Single check points were performed throughout the
project.
A total of 3022 in-place density tests were performed by the sand cone (ASTM
D1556-64) and nuclear gauge (ASTM D2992-78) methods during site grading. Where
the field tests indicated that the specified degree of compaction had not been
obtained, the area was reworked and additional compactive effort was applied until
desired compaction was achieved and verified by additional testing.
MOISTURE CONDITIONING
We understand the lots will not be built upon in the next few months.
Recommendations regarding potential expansion characteristics at the present soil
moisture contents would not necessarily be valid after the subgrade soils have lost
significant moisture. Accordingly, our recommendation is to moisture condition (pre-
soak) selected lots before construction.
GEOLOGIC CONDITIONS
Geologic observations and mapping were performed during rough grading of the
subject tracts. The purpose of these observations were to:
1. Confirm subsurface conditions as observed in our geotechnical investigation.
2. Evaluate geologic conditions and features exposed on newly created cut and
fill surfaces within the tract.
3. Provide additional geotechnical recommendations for project grading.
Geologic information obtained during mapping of building pad areas, slope exposures
and street subgrades is included in Appendix A and on Drawings 1 through 9.
~arth Materials
Earth materials exposed at surface grades within the tract consisted primarily of
compacted soils in fiil areas and Pauba Formation bedrock (Qp) in cut areas.
Exposures of colluvial (Qcol) and alluvial sediments (Qaq were very limited as these
materials were excavated to expose competent material prior to placement of
compacted fills. Areal distribution of the fill and bedrock cut areas are shown an
Drawings 1 through 9 and briefly discussed below. 8
88-81-148-03
ConMne Ccmulbnb IM~M EmDire 3
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Fill IMa~ Svmbol: Within Black Line Borderl
Fill materials consisted of processed mixtures of on-site soils and Pauba Formation.
The cut portion of cut/fill transition lots were overexcavated and were inciuded in the
areas mapped as fill.
Pauba Formation IMao Svmboi: Qo, Qoss. Qosltl
The Pauba Formation of late-Pleistocene age (Kennedy, 1977) consists of distal
alluvial fan and braided channel deposits, with numerous intra-formation
unconformities. Sedimentary features characteristic of the depositional environment
such as channel features, lenses, and cross-bedding were observed in cut areas on
slopes and building pads.
Lithology of the Pauba Formation is highiy variable, consisting of poorly interbedded
to massive, moderately to weli consolidated, fine to coarse sandstones, siltstones,
and claystones. Bedrock siructures within the Pauba Formation varied over relatively
short distance. Bedding attitudes recorded at the site indicate strikes ranging between
northeast to northwest, with dips varying from nearly horizontal to approximately
10°. Bedding attitudes of localized depositional channel deposits and lenses were also
recorded. Attitudes of lithologic layering within these sedimentary features varied
with strikes ranging between northeast to northwest and dips varying from nearly
horizontal to approximately 60°. Numerous horizontal and gradational bedding
boundaries were also observed. The Pauba Formation was mapped mainly as
undifferentiated (Qp). Distinctive sandstone (Qpss) and siltstone (Qpsit) lithologies
were mapped within undifferentiated Pauba.
Sandstone (Qpss) units exposed on lots 34-2, 35-2, 40-2, 49-2, 50-2, 51-2, 52-2,
53-2, 542, and 102-2 of Tract 24131-2, and Lots 25-3, 26-3, 27-3, 28-3 and 54-3
of Tract 24131-3 consisted of clean sands with little or no cohesive binder. These
earth materials are judged to be more susceptible to erosion than other site materials.
This condition should be anticipated during construction and mitigated with
appropriate landscaping and maintenance.
Faults Exoosed During Grading
No fa~lts were observed or mapped during site grading for the subject tracts.
Cut and fill slopes have been graded at 2:1 (horizontal:vertical). No adverse geologic
structures were observed on these slopes.
Groundwater Seeoage
Groundwater seepage was not observed on the slopes, buiiding pads, street
subgrades or canyon bottoms during site grading. ~
88-81-148-03
Conv~na Con~uM~nn In1~nA Empire
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CONCLUSIONS
• Results of density tests in fill indicate a relative compaction of at least 90
percent of the laboratory maximum dry density. A total of 3022 field density
tests were performed and their approximate locations are shown on Drawings
1 through 9.
• A statistical analysis was performed on the distribution of relative compaction
results. A histogram of this is shown on Figure 2.
• Based on the results of our observations and testing, it is our opinion that the
earthwork associated with the grading of the site has been performed in general
accordance with ~ecommendations presented in the referenced reports.
• Expansive soil conditions have been evaluated for each lot. Lots that exposed
materials considered to have low expansive potentiat were visually classified.
Representative samples of the soils near pad grade were recovered for
classification and expansion index testing. The results of the tests are
presented in Appendix A. Classification of each lot, based on these test results,
is presented on Table 1.
• Groundwater was not encountered during grading, and is not expected to
adversely impact development of the site as proposed.
• Fill slopes have been graded at 2:1 (horizontal:vertical) or flatter, and are
considered to be grossly stable.
• Cut slopes graded at 2:1 (horizontal:vertical) or flatter are anticipated to be
grossly stable due to the generally massive nature of the bedrock materials and
the lack of continuous adverse geologic structure. Some surficial erosion may
occur prior to the establishment of vegetation, particularly where there are
sands with little or no cohesion.
• Although grading for the lots is considered suitable at the time of completion,
natural weathering and degradation may occur over time in the near-surface
soils within the graded areas. It has been our experience that deterioration of
surficial soil conditions may develop if a significant time period elapses before
construction.
~ Properly compacted fills will settle due to their weight. The amount of
settlement will depend on fill thickness and future changes in the moisture
conditions. Maximum expected settlements are on the order of about 1°h of
the total fill thickness.
88-81-148-03
Conwna Con~uh~nt~ Ml~nd Empire
1~
5
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REUTIVE COMPACTION, Pereent
Soil Type:
Munber of Testa: 3021
Averape: 92.0
Stardsrd Devi~tian: 2.20
Coefficient of Verietim,X: 2.40
Camients:
XISTOGRAM OF Cp1PACTIOM TEST RESULTS
' P~lonis Del Sol / Mesa Nanes Project No. \`
Temeeula, Glifornia 88•87-748•03
Cornerse Ca+sultents Inland E~ire
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RECOMMENDATIONS
Foundation Design
The proposed structures may be supported by conventional (continuous) footings or
isolated spread footings. Post-tensioned slabs may be used on lots that have highly
expansive soils exposed at pad grade. The depth of embedment and reinforcement
should be determined by the soils expansion potential as shown on Table 2,
"Suggested Guidelines for Design of Foundation/Slab Systems". Alternatively,
expansive soils may be removed and replaced with low expansive fill to a depth of at
least 3 feet. We will review any further alternatives that may be proposed by the
structural engineer. Footings may be designed using an allowable bearing pressure
of 2,000 pounds per square foot, which may be increased by one-third for short
duration loadings such as wind or seismic forces. Footings for structures or retaining
walis should be setback from slopes in accordance with the Uniform Building Code
(1988 editionl, Section 7011.
Post-tensioned Siabs
in lieu of the recommendations presented on Table 2, building foundations on highly
expansive soils may be pre-soaked and constructed with post-tensioned slabs. For
design purposes, a differential movement of about 2 inches over a 15 foot span
should be expected.
Pre-Soaked Building Pads
Due to medium expansive soils, the following lots require pre-soaking prior to
constructing concrete slabs: 43, 99, 52-1, 32-2, 55-2, 71-2, 77-2, 78-2 and 46-3.
Guidelines for pre-soaking are shown on Table 2 under sub-grade Moisture
Requirement at time of construction.
Slabs-on-Grade
Siabs should have a minimum thickness and reinforcement as recommended in Table
2. All loose or disturbed subgrade areas should be recompacted prior to concrete
pour. Polyethylene plastic moisture barriers of 6-mil thickness should be placed under
the slabs. The moisture barrier should be protected with 2 inches of sand placed
above and below the moisture barrier to prevent punctures and to aid in the concrete
cure. Joints should be lapped a minimum of 6 inches and properly sealed.
88-81-148-03
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TABLE 2 '
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SUGGESTED GUIOELINES FOR DESIGN OF FOUNDATION / Sl.ABS SYSTEMS 'I
FOUNDATION SYSTEM TYPE I TYPE II TYPE II1 TYPE IV TYPE V I
EiOa~sion Po1~nHal Ver7 Lor+ Low Madium MIpA Very HiQA ~'~,
Eapanzon Indes (E 1.J O- 20 21 -50 51 - 90 91 -ISO AEove ISO ~
foolinp D~D~~ One Two One Two On• Tro On~ Two On~ Two ''~,
slory slory siory story story slory story stor7 stor~ slor7 '~.,
Ptrim~ler 12~~ IB~~ 12" 18" 18" 18" IB" 18~ 30~ 30"
'~
Inl~rlor 12~~ IB" 12'~ IB'~ 12'~ 18° 18" IB~ IB~~ .
~g" .
Foollnq pein(oreemtnt N~~ ~'~k 4 Bar
' 1-YF 4 Bor 2'/~ 4 Bon 2-~~ 4 Bars
Mondatorr Top fi Boltam Top 6 Botfom Ta0 8 Botlom Tap 9 Botfom
12"X12"W/ 12"X12" W/ I2"X12"W/ IB~X18°W/
GaraQ~ Grod• B~am Not
At Door OD~~Inq
Mandatorr I'/t 4 Bor 1'ff 4 Bar 1'0/ 4 Bat I'>R 48or
To0 9 Boltom ToD B Botfom Top B Bottom Top B Botlom
Floor Slab Thlekn~» 4" Naminol 4" Nominal 4" Naminal 4~ Actual 6" Nominal
Floor Siab (l~infote~mmt Nol
Mandatorr Yk 4 a118~ o.c.
~v~a~~in0• 6"%6"'JflO/>FIO 6~X6"-f 10/>~q 6~X6"-fR6%06" EacA Woy
Gorepaa Nol Manaolor~ fi X6"-T y~tlp/>p~p 6~~X6~~-OC6/YF6 6~X6~->k6/>F6
Svbprod• Moisivre C~tlnun (~~Cinun 120%. of Ov~~~m I20•/. 01 Oplimum 1207. of Opti~m
Requlr~m~nl at Tim~ M ~ Mol~tur• to 12" Moisture l0 18~ Moislur~ to IB"
_ of Conf~rudion ~~9~~r ~~y~~~ ~ B~low Slob B~low Slab B~low Slab
FOUNDATION RECOMMENDATIONS
~
PAIOMA d~t SOL Mast~r Vl~n Community ~ P`q"' No.
T~m~eula. Calt}ornfa 88'81-148-0~
}or• M~sa Mom~s
' ~ CONVERSE CONSULTANTS INLAND EMPIRE ~
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Lateral Earth Pressures
Resistance to lateral loads can be provided by friction acting at the base of the
foundations and by passive earth pressure. A coefficient of friction of 0.33 may be
assumed with the dead load forces. An aliowable passive earth pressure of 200 psf
per foot of depth to a maximum of 2,000 psf may be used for the sides of footing
poured against properly compacted fill or natural soils. The allowable passive pressure
may be increased 33% for lateral loading due to wind or seismic forces. Retaining
walls should be designed for an equivalent fluid pressure of 30 psf per foot of depth.
Adequate wall drainage, consisting of subdrains and weep holes, should be provided.
Preliminarv Pavement Desiqn
Prior to placement of base course and asphalt, the upper 12 inches of subgrade soils
should be scarified, moisture-conditioned and recompacted to at least 90°/a relative
compaction. Based on R-value test on representative samples, preliminary pavement
sections recommended for design are presented on Table 3. Traffic index information
present on Table 3 was obtained from RBF Engineers. Minimum thickness of asphalt
concrete IAC) based on information provided to us by the County of Riverside and the
City of Temecula, are as follows:
MINIMUM
TRAFFIC AC
INDEX THICKNESS. Ft.
5.0 0.21
5.5 0.21
6.0 0.21
6.5 0.21
A minimum thickness of aggregate base (ABI is not mandated by the building officials.
However, we recommend that a minimum of 0.33 ft. (4 inches) thick layer of Class
II AB be provided beneath all pavements. The base course provides pavement support
as well as drainage beneath the pavement. Improvement methods such as lime
treatment of the subgrade soils, may be effective to improve the pavement
characteristics and to reduce the pavement sections presented in Table 3. Preliminary
evaluation of lime treatment indicates that 2% by weight lime mixed with the on-site
soils to a depth of about 6 to 8 inches will resutt in an R-value of greater than 60.
88-81-148-03
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ConMn~ Coroukurt~ Inlsrd EmOiro 1 ~
Minimum AC and minimum AB will, therefore, be sufficient to support the anticipated
Traffic Indices (TI) up to a TI of 6.5. Additional R-value testing may be required prior
to paving to verify the appropriateness of the recommended pavement sections
presented on Table 3, which are based on present road department guidelines.
Site Drainaae IPost-Constru .rinn~
Adequate positive drainage should be provided away from structures to prevent
ponding and to reduce percolation of water into the foundation soils. We recommend
that slopes for surface drainage be constructed at 2% to 4% in landscaped areas and
1°~ to 2% in paved areas. Planters and landscaped areas adjacent to the building
perimeter should be designed to minimize water ponding and infiltration into the
subgrade soils. Planters adjacent to foundatio~s should have a drainage system to
conduct water to a collection point for disposal. Homeowners should be advised of
their responsibility for maintaining adequate drainage.
Slope drainage devices should be constructed in accordance with Chapter 70 of the
Uniform Building Code (1988 Editionl. Lot drainage should preclude the possibility of
flow over slope faces with the use of brow ditches, earth beams and other methods.
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TABLE 3
ASPHALT PAVEMENT SECT10N5
INTERIOR STREETS
TAACT 24131
Reeommended Reliminery
Pevement Saetion
Traffie
Index Asphslt Base
St~eets jJ, R-Velue f~ ll
Ye flezo 6.6 . 40 0.25 0.69
Y~e Fbre 6.6 36 0.26 0.60
Ym Candelede 6.6 30 0.25 0.67
Vis Cordero 6.6 30 0.26 0.67
Corte Durezo 6.0 30 0.25 0.48
Ya Bande 6.6 30 0.26 0.67
Calle Cerebena 6.6 14 0.26 0.84
Corte Llamae 6.0 14 0.25 ~ 0.69
~a Maya B.5 14 0.25 1.14
Via Cesario 6.6 47 0.25 0.30
Ye Cirillo 6.6 13 0.25 0.84
Corte Astorye 6.0 13 0.25 0.69
Celle Matero 6.6 13 0.25 0.84
Via Jesso 8.6 13 0.25 1.14
Calle Avelle 6.5 11 0.26 0.88
va Nias 5.6 36 0.26 0.49
Vie Jumilla 6.6 22 0.25 0.70
Corte Illore 6.0 36 0.26 0.42
Cone Gerdeno 6.0 22 0.26 0.66
Cemino Herencia 6.6 22 0.25 0.70
Ye Mejie 6.b 35 0.26 0.72
Corte Argento 6.0 47 0.26 0.21
Ve Mnedo 6.6 7 0.26 0.94
Corte Davila 6.0 7 0.26 0.78
Cemino Caruna 6.6 7 0.26 0.94
Ye Sejo 6.6 36 0.26 0.72
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Sio~e Protection and Maintenance
Proposed siopes should be planted as soon as possible after construction. Siopes will
require maintenance through time to perform in a satisfactory manner. In most cases,
slope maintenance can be provided along with normal care of the grounds and
landscaping. Cost of maintenance is less expensive than repair resulting from neglect.
The presence of permeable sandstone materials over less permeable siltstone and
claystone material within the Pauba Formation could trap infiltrated water (landscape
irrigation and/or rainfall) and produce seepage at the surface exposures of these
contacts. Fault traces containing gouge zones may also act to restrict groundwater
flow and surface infiltration. Seepage conditions daylighting out on the slope surface
may produce nuisance raveling and possible instability. Local drainage and/or seepage
collection devices may be required to be installed by homeowners if these conditions
were to develop in the future.
Most hillside lot problems are associated with water. Uncontrolled water from a
broken pipe, excess landscape watering, or exceptionally wet weather causes most
damage. Drainage and erosion control are paramount in regards to long-term slope
stability and performance. It is important that the drainage patterns and slope
protection provisions be established at the time of fine grading and maintained
throughout the life of the project. The provisions incorporated into the graded site
must not be altered without competent professional advice.
Terrace drains and brow ditches on the slopes shouid be periodically maintained and
kept ciean of debris so that water will not overflow onto the slope, causing erosion.
Landscaping on the slopes should disturb the soil as little as possible and utilize
drought resistant plants that require a minimum amount of landscape irrigation. Care
should be exercised to prevent loose fill from being placed on slopes during
construction and Iandscaping. Installation of subdrains or french drains may be
required if seepage is observed.
Watering should be limited or stopped altogether during the rainy season when little
irrigation is required. Over-saturation of the ground can cause subsidence within
subsurface soils. Slopes shouid not be over irrigated. Ground cover and other
vegetation will require moisture during the hot summer months. However, during the
wet season, over irrigation can cause ground cover to pull loose, which not only
destroys the cover, but also results in serious erosion. Homeowners should consult
a professional landscape architect for planting and irrigation recommendations.
• A suitable proportion of slope plantings shall have root systems which will
develop well below 3 feet, such as drought-resistant shrubs and low trees, or
equivalent. Intervening areas shall be planted with lightweight surface plantings
with shallower root systems. In any event, lightweight, low-moisture planting
shall be used.
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• Rodent burrowing, small concentration of uncontrolied surface/subsurface
water, or poor compaction of utility trench backfill on slopes shall be repaired
and controlled as soon as possible.
• If completion of new slopes occurs during the rainy season, contingency plans
shall be developed to provide prompt temporary protection against major
erosion/sloughing. Offsite improvement shall be protected from site runoff.
• Any erosion damage which occurs prior to the completion of the project shali
be repaired by the Contractor.
Onsite Trench Backfill
Trenches should be backfilled and tested in accordance with procedures described in
Section 306 of the "Standard Specifications for Public Works Construction" and the
referenced reports. it is anticipated that the native soils wiil not be suitabie for jetting.
Compaction will probably best be achieved by moisture conditioning the soils, placing
the material in lifts and applying mechanical efforts on each lift.
Continuina Observation and Testina Services
Observation and testing should be conducted by CCIE at the following stages of
construction:
• Concurrent with trench backfill procedures.
• Concurrent with subgrade and aggregate base preparation and compaction.
• Pre-soaking of expansive soil lots at time of construction.
• When any unusual conditions are encountered.
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LIMITATIONS
The conclusions, recommendations and opinions developed during the course of
CCIE's field assignments were based on our observations and experience, and on the
results of field and laboratory testing performed in accordance with applicable ASTM
standards. Based on these tests, observations, and our professional judgement, it is
our opinion that the compacted fiiis referred to in this report meet the intent of the
project specifications and the recommendations of CCIE.
Our field testing was performed at random locations and at various time intervals
during the fill placement operation. CCIE did not actually sample or test absolutely
every portion of the fill material placed at this site. Our test results are considered
representative of the material tested within the compacted fills.
This report presents opinions formed as result of our observation of fill placement.
We have relied on the contractor to continue applying the recommended compactive
effort and moisture to the fill to meet the project specifications. Tests were made of
the fill to calibrate our observer's judgment, and to provide data on the overall
compactive effort. These tests are not the sole basis for opinions on whether the fill
meets the specifications.
CCIE professional services were performed in accordance with the prevailing standard
of professional care as practiced by other geotechnical engineers and engineering
geologists in this area of California. We make no other warranty, either express or
implied.
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REFERENCES
• Converse Consultants Inland Empire, "Geotechnical Investigation, Tentative
Tract 24131, Pianning Areas 15 and 22, Portion of the Meadows, Rancho
California, California", Dated December 23, 1988 (CCIE Project No. 88-81-148-
01-DI.
~ Converse Consultants Inland Empire, "Standard Earthwork Specifications,
Western Portion of the Meadows Master Plan Community, Temecula,
California", dated March 8, 1990 (CCIE Project No. 88-81-148-03).
• "Rough Grading Plan Tract No. 24131, 24131-1, 24131-2 and 24131-3, City
of Temecula , Sheets 1 through 10, prepared by Robert Bein, Wiiliam Frost and
Associates, dated March 7, 1990.
• Pacific Soils Engineering, Inc., "Fault Study 1400 ± acre Vail Meadows Project,
Rancho California, County of Riverside, California", dated August 17, 1987,
Work order 400082F.
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