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HomeMy WebLinkAboutAs Built Geo & Final Compaction Rough Grading~~~ ~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 \ ~ R~~C~1~~~~ ~ ~~~~"~~ : ; '~~ 1 `~ 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 /r~ ,`~ 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 QRpEESSlp~yy O ~ ~~~~ `4~~ c. x£[-:..~ ~.;a ~j ~ ~IU' ' ~i7 P..-J..'1 . tG ~\ _.~.~ . . ~~C ``!'- ~`.` ^ '%~~,' _ U~. ' : J "?,'~ ~f ~~:l~~v'! ark B. Schluter, CEG 1415 Senior Geologist ~~~•S~~ BED ~G ~~~o%~ .~ . ~~ Ne. 1415 p; ~ CERTIFIED ~ *' ~ ENGINEEA~NO • * , S GEOLOGIDT . ~ sl~r'••.....••' P~a~Q' EOF CAi~F~ ~ ~_ 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 ~ 1 a . TRACT 4134.-a,-2,-3 >. -... ~fiF ~ v•24133,-1 : ~ TRACT ~~:~` 24135,-1,-2,-3 T:`~ 4- ~ ~e~ ~ ` ~-~ ~~~e~ "9 t ~ir a : ' ,~°;. '~ ,, 3 n' b • u v 0 u e e 0 0 < suba ~r ~ ( A f m..e. ~ Pmm..e~;~ i ~ ~ ~ » !!~J ~~ ~~+0~ C TRACT ` yi' . 7 24132-1 i~'~~/ -'w. ~; • , ,c~' ,' •, ~ ~ ~ ~~ _ 3 •:. ~~ ~..~~~• , .~ GL 1 ~ TRACT 24t31,. ,~ -3 . -~~ 2~ : .. - 5 A ~ ~T~~W ^~`~.~~ -: TRACT : ; 24136 ~ t ,r , ~, ! : ~y ... •%~. :'"__'-'~ r~J• ~ yl~e ' :. ' =~~,~.::; e ~ . ~ ~ o ~ ° , E `~ p Z~ . ~~~ ( ~ _. ;. ~~; TRACT 'a.' .." ' ~~~ 2a~as=• ss t~ r -O ~~ n ~ K~-n t~.c ~or , .~b~.+• :n•~~~ ... ~T- -~ °y. - .r „ ' ~~ - o,~`.. o,,.~, a: , ~ n ~ ~~`o" ~~aP ~e.e~ 1 ' ~ `° -f ' ' "'v~z" ~ ;;•~.~ ~.~ . ~:. ; fl.., . __ '.;, ; ~;,r,,~ _~~ ~.~ . ~ ... a - ~ "~ ji~ 7v~,R4:r~<~:t°" a r n~ ~t i i• ~ ~o~ ~~5~-.i•~'o~~ !i~ • ... a~ ~~Jj .~ _ _„ ~,.,_'`m~_~~. _ .~.. _ . y __' ~ ._... . ~.~_.' • _ ___" '.,~.A 1 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 , ', 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 4 r 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 ~o 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 M ~ M ~ N ~ O ~ ~ N ~ d ~ a ¢ <"> ~ y ~ ~ N a m c . ~ V C ~ `~ O '- tn 'y M ~ ~ ~ V a c~ X ~' W ' O ~ J M ~ a N U W ~ 0 ~ ~ ~ ~ rn ~ a ~i ~o r- N 00 N r M N ~ ^ ~ N ~ ~ IA N ~ T n M ~ ~ N a f'~ ~ ~ LL'1N ` ° ~ ~ ~ ~ ~ r c ~,n w ~~ °~o v ~ N e-N fD a~.~. ~ N~ f~ N~ ('~ ~ ~ N ~ f7Ct~~ LL7 ~ ' 3 0 p O~N N(p V o o 0 ~ ~ ~ N c~~1D~ ~Na J fV ~ ~« C^p ~" ~~NN .~.~^ f7 nOaD~~~O j ~~N^ ~ ~ N Na i N~^ ~ ~ O ~ N O~ O ~ O `~ `~ f~ f0 eY lCY ~ ~" . .- "" ~ ~• .--e-f")I~CD ..~ ~f7NNN ~f7 ~ ~ ~ n ~C700~N ~ 3 ~~ ~ ~ ~ M~ ~ 0 N N ~ f7 ~' QN1~~1~ O > p ~ N ( ~ ~ ^ .~ 1~ ~ ~ 00 .- M ~ ~ ~ y C C Z W G ~, Q X W J n ~ ~ WaC • ~ ~ Q ~ ~ ~ ~ ! ~ 1 ~ ~ ~ ~ ~Z 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 ~~ Convens Con~uh~nt~ InI~M EmOiro ~ ~~ a c I ° ~ ' n a G O I ~ O O G < i TABLE 2 ' ; 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 ~ r ~ 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 \~ 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. 88-81-148-03 ~~ Conwn~ Con~uh~nb IMand EmOin ~ ~ . 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 88-81-148-03 Conv~ne Con~uhsnt~ IM~nd Empin 1~ 12 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. 88-81-148-03 \8 Convana Can~uttant~ Inl~nd Empire ~ 3 • 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. ~~ 88-81-148-03 Unwns Con~uk~nt~ InI~M EmO~ro ~ 4 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. 88-81-148-03 Conwne Con~uh~nn In1arW Empin 15 ~ ,~ . . ; _ 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. 88-81-148-03 Canwn~ Camukart~ Inl~nd Empin 16 Z~