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HomeMy WebLinkAboutCT 79-26; 17 UNIT CONDOMINIUM PROJECT; PRELIMINARY SOIL INVESTIGATION; 1980-08-22•• PRELIMINARY SOIL INVESTIGATION FOR THE PROPOSED 17-UNIT CONDOMINIUM PROJECT IN CARLSBAD, CALIFORNIA • Augus t 22, 1980 Project Number -00051 Prepared for: Thomas & Sowards Engineeri~g, Inc. 21 5 S. Hwy 1 01 Suite 101 Solana Beach, CA 92075 Prepared by: Torrey Pines Consu1ting 'J.a5 V; a de-}a-\fatTe TORREY PINES CONSULTING I 2145 Newcastle Avenue • Cardiff·BY·The·Sea, CA 92007 , . August 22, 1980 Thomas & Sowards Engineering, Inc. 215 S. Hwy 101 Suite 101 Sal ana Beach, CA 92075 • Subject: Preliminary Soil Investigatian far the Proposed 17-Unit Candaminium Praject In Carlsbad, Califarnia, Legal Descriptian: Lots 387 and 388 af La Costa South, Unit No. 5 accarding to map no. 6600. Gentlemen: In accardance with yaur request, we have perfarmed a Preliminary ,S6il Investigatian at the subject site. Our investigatian was perfarmed to. pravide preliminary geatechnical data to. ,aid in averall site planning and develapment. This repart presents the reuslts af aar fteld and labaratary investigation, as well as gealagic and soils engineer-ing ana lysi s, whi ch are the basi s for aur findings, co.ncl uS'i ans and r.ecammenda- tians. If yau shauld require any clarification of the abave, dan't hesitate to gi ve us a ca 11 . Very truly yaurs, TORREY PINES CONSULTING Dennis E. Zimmerman, P.E. C26676 Praject Engineer DEZ:mh i ,Dan D. GaaQwin Praject Manaqer TABLE OF CONTENTS Letter of Transmittal Tabl~ of Contents Introduction Layout of Report Scope of Services Proposed Development Site Description Location Map, Plate No. 1 Geology Regional Geologic Map, Plate No. 2 Field and Laboratory Investigation . Site Plan, Plate No.3 Site Photographs, Plate No. 3A Conclusions and Recommendations Limitati ons Appendix A -Subsurface Investiga~ion Exploratory Test Pits, Tl -T6 Appendix B -Laboratory Testing Unifi ed Soil Cl assifi cati on Chart Tests Results Appendix C -Recommended Grading Specifications ii • i ; ; 1 1 1 1 2 3 4 5 6 7 8 9 -15 16 17 18 -23 24 25 & .26 .. 27 & 28 29 -31 INTRODUCTION • PRELIMINARY SOIL INVESTIGATION FOR THE PROPOSED 17-UNIT CONDOMINIUM PROJECT IN CARLSBAD, CALIFORNIA The report presents our nplnlons resulting from our soil investigation on the subject property. Our i nvesti gati on was perfo'rmed on ft.ugust 12, 1980. The purpose of this investigation was to evaluate the site from a geologic and soils standpoint and to provide preliminary recommendatiolls for your use in overall development. LAYOUT OF REPORT The body of the report contains the text of our findings and ·r.ecommend~tions. Details of our field and laboratory work are presented in the appendices at the end of the report. Key statements in the test are underl ined.. SCOPE OF SERVICES The scope of services performed in the course of this investigation inclUded: 1. Review of published and unpublished reports and maps pertaining to the subject site and its vicini'ty; 2. Geologic mapping 'of the site; 3. Subsurface exploration consi~ting of six backhoe pits~ 4. Laboratory testing of representative soil samples obtained dllring the field investigation; 5. AnalysiS of field data and preparatiori of this report, including our findings, conclusions and recommendations. PROPOSED DEVELOPMENT Proposed development of the irregular shaped site is for 6 buildings comprising a total of 17 condominium ~nits. Structures will consist of two stories of wood-framed construction over ·a first level 'par,king' garage. The parking garage will utilize both 'wood-framed and concrete. masonrY unit construction. -1- , . SITE DESCRIPTION The subject site is located on the east side of Romeria Street, north of La Costa Avenue and south pf Gibraltar Street in the La Costa a~ea of the City of Carlsbad, County of San Diego, State of California. The subject site has previously been graded into two separate 10ts, the· southern lot being about 15 feet higher than the northern'lot: Both lots are flat, with cut and fill slopes surrounding each. A condominium complex exists to the south of the site, about 15 feet higher in elevation than the adjacent subject site. A housingsubdivtsion is present to the east, standing atop an approximately 60 foot hign slope .. To the north are located vacant graded lots. Romeria Street borders on the west. Geographic relationships are shown on the Location Map, Plate No .. 1. The site consists of poorly compacted material. Both pad~ are cut/fill pads with fill extending to 171-611 below existing pad grade for the southerH lot. Running water was encountered at various depths on both lots. -2- LOCATI·ON MAP 17 (/.),'nl:.i C.oniu.fUng --' 0 'ttl:. !:J ;..I" ROMERIA STEET CONDOMIN"IUMS PROJECT NO. ,D,ATE PLATE I 00051 8-22-8.0 NO, 1 -3- GEOLOGY The subject site is located in Carlsbad, California. Underlying the site according to the U.S. Geological Survey Map, San Diego Quadrangle, are Eocene marine sedimentary rocks of the Tertiary Age. . No faults are known to pass through or near the site. The Regional Geologic Map, Plate No.2, shows the subject site and the geologic setting of the area. -4- \. \ \ "-\ \ \ '''' •. 1 Scale=1:250,OOO ~, I nUIII \.Inrt REGIONAL GEOLOGIC MAP RnM~RIA STREET COND0MfNIUMS PROJECT· NO. DATE PLATE 0005.1 8-22-80 NO.·? -5- , I . ! FIELD AND LABORATORY INVESTIGATION The subsurface investigation consisted of 6 test pits trenched to a maximum dpeth of 19 feet. The locations of the pHs are shown on the attached site plan, Pl ate No.3. The trenches were carefully logged and sampled by our personnel. Site photographs are shown on Plate No. 3A. Represenative samples of the various soils encountered in the trenches were returned to the laboratory for evaluation and approriate testing. Logs of the test pits and descriptions of the laboratory tests are presented in Appendices A and B, respectively. -6- ./ \~­ Vacant .Lot \ , \ \ \ I I) Existing Subdivision ----1: __ \ Existing Condominiums , . ;".....-. ". I I ~ -::..J I I r:::::=ll I I T1 ,\ \ ( --. ,--.,\., I~T4 \' ?/---" 1/ --. --... Romer'ia Street r::::::::J T6 = Approximate location of test pits. SITE ,P.LAN ROMERIA STREET CONDO~INIUMS PROJECT 'NO. DATE PLATE ~------------~--~--~----~ 00051 8-22-80 NO. 7' -- 3 POOR QUALITY ORIGINAL ·.S Southerly lot looking southeast at southern fill bank. Southerly lot looking east. , . S I FE PHOTOGRAPHS' , RO~ERIA STREET CONDn'~pWIf'<1S PROJECT NO. DAre: PLATE f----------~~4-----~~--~~ 00051 8-22-8,0 NO. 3/\ -8- CONCLUSIONS & RECOMMENDATIONS A. General The site is suitable for the proposed'development from a peoloqic and soils engineering. standpoint, with,in th~ f.ramework of our recommendations. There are, however, certain constraints whic~. must be taken into account. The contraints, conclusions and recommendations follow. B. Slope Stability We recommend that any required permanent cut or ,fill,slopes be constructed to an inclination no steeper than 2.0 horizon'tal to 1.0 vertical. Also, all existing slopes within the ptoject site should be reduced to 2.0 to 1.0. Placement of fill near the tops of slopes should be carried out in such a manner as to assure that loose, uncompacted soils are not sloughed over the tops and allowed to accumulate on the slope face., The on-site soils will be highly susceptible to erosion where exposed on slopes. Therefore, the project plans and Specifications shoul d contain a 11 necessary features. and constructi on requi rements to prevent erosion of the slopes both during and after constructidn. Slopes 'and other exposed ground surfaces should be approp'riately- planted with a protective ground cover. C. Gradinq and Earthwork 1. Clearing Prior to. gradinq, the site should be cleared of s'urface obstructions and stripped of brush and vegetation. Obstructions which extend below finish grade should be remov,ed .and ,replaced with compacted fill. Vegetation and debris from the 'clearinq operation should be removed from the sfte. -9- 2. Existing Fills and loose 'Natural Soils Any existing fil,l material and loose natural soil that is not removed by the required site excav'ation work 'should be over- excavated down to firm natural ground and replaced as compacted fill. The need for and extent of over-excavation work to remove existing loose materials should be determined by the' $oil engineer in the field during the site preparation work. The minimum depth of removal shall be 5 feet below exjsting g.r.ade. This minimum dej)th of removal is necessary because of the Tow strength of the existing soil material due to the following factors, (1) portions of the existing fill is less than the required 90% relative compaction and (2) the onsite soil is critically ~xpansive, causing severe cracking from shrinkage and expansi'on during wetting· and drying of soil materials. 3. Scarification and Processinq of Surface Soils Fol10win~ over-excavation of unsuitable materials, all areas of the site to receive fill and/or other improvements should be scarified to a depth of 6 to 8 inches, brought to near optimum moisture conditions, and compacted to at least 90 percent relative compaction. 4. Ri ppabil i ty The on-site soils and bedrock materials are' expected to be excavated using conventional earth-moving equipment. 5. Over-excavation of Transition {Daylight) Pads If a dayl i ght pad shoul d occur where the building \>li.11 'p"3.rtly be underl ai n by compacted fill and partly by bedroc'k and/or -10- natural soil, the cut portion of the lot should bp-over- excavated to a depth of at least 4 feet below finished, pad grade and replaced with compacted fill. 6. ~1aterial for Fill All existing on-site soil and bedrock materials ~re suita~ls for reuse as fill. Fill materials should, in general, not contain rocks or cobbles greater than 6 in6hes in largest 'dimension. However, larger rock fragments may be incorporated into the lower portions of fills, provided the method of spacing and compaction is apr roved by the soil engineer. 7. Compaction and Method of Fillina All fill at the site should be comoacted to a minimum relative compaction of 90 percent, based upon ASTM Laboratory Test Oesiqnation 0-1557-78. Fill ~hould he compacted by mechanical means in uniform li~ts of 6, to 8 inches in thickness. Fills constructed on natural slopes ~aving an inclination steeper than 5 horizontal to 1 vertical should be keyed and benched into bedrock or competent natural ground. Compaction of slopes should be achieved by overbuilding, the slopes laterally and then cutting back ~o the design line and grade or by back rolling with sheepsfoot at'frequent intervaJs as the fill is placed, followed by final rolling of tbe entire slope. Feathering 'of fill over the tops of slopes should not be permitted. /l.ll fills should ~)e ~laced am! grnding pe,rformed in accordance wit~ applicable local gradinq ordinances. 8. Trench Backfill Pipeline trenc~es should be backfilled with compacted fill. Backfill material should be placed in lift thickh~sses armropriate to the type of cOf11paction equipment utilizet;! and, comoacted to 90 percent bv mechanical means. -11- 9. Drainage' Due to the excessive running water found es~entia11y at all depths, including the contact line between the fill and form~t;Qnal s.oi1 rna teri a 1 and due to the fact that the site is located on a natural drainage course, we recommend that a french drain system. be inst~lled at the site. The french drains should be installed behind th~ retaini·ng wall footings, extend a minimum of six feet below the retaining w?\ll footings, be continuous to and drain into the street, have a minimum 3% fall and be a minimum of 18 inches wide. At the bottom, place a 6 inCh ~iameter perforated rigid pipe with the perforations facing· down wi.th a minimlJm of 6 inches of gravel surrounding the pipe. Th~ last 20 feet of pipe at the outlet shall be non-perforated pipe. The french drain sha11 be backfilled with Class 2 permeable material. Positive surface gradients s·hould. be provi~ed adjacent to buildings so as to direct surface water away from foundations and slabs toward suitable discharge facilities. 'Ponding of surface water should not be allowed adjacnet to structures or on pavements. Water should not be allowed to drain over slopes. 10. Recommended Gradinq Specifications Grading should be done in accordance with Appendix C, "Recommended Grading Specifications." D. Foundation and Slab RecommendationS 1. ~ecommendations for Expansive ~oils Field observations and laboratory testing indicate that the expansion potential of the finished pad soils will be in the critically expansive range. Recommendations for foundation and slab design, cons;rl~rinq the expansive soil conditions, ar~ as follows: -12- a) All footings should be 24 inches deep below slab subgrade, continuous, and contain 1 -Nb. 5 bar top and ,bottom. b) Living area floor slabs s~ould be a minimum of 4 inches thick with 6X6-6/6 welded wir~ fabric at midh~ight over 1 inch of sand over 6 mil visoueen moisture barrier dver four inches of gravel or sand base. c) Garage floor slabs should be 4-inches thic'k \,lit.,: F.X'6-f./6 \'/e 1 ded wi re fabri c, i so 1 ated from stern \1a 11 footi ngs, oyer four inches of gravel or sand base. No moisture nar'rier .is required. d) Pre-soak under all slabs, to a depth of 24 tnches to 3% +3% above optimum moisture content . .=-• 2. Soil Bearing Pressure Structures may be supported on conventio'1a1 shallow footings' ' bearing in bedrock, firm natural ground or compacted fill. At, a minimum depth of 24 inches for two or three--stdry buiTdi"ngs" footings may be desi!J.ned for an allowable .de'ad plus li:ve load bearing pressure of 1200 pounds per sq~are foot.' Th~Se va 1 ues may be increased by one-thi rd for short-term loads, , including wind or seismic. Footings should have a mini~um width, of 12 inches. Settlements under buildinq loads are ~xpecterl to be w1thin tolerable limits for the proposed structures.' We estimate that post-construction differential settl~ments across anyone building will not exceed 3/4 inch. 3. Lateral Loads Lateral load resistance for the buildings and retaining \'/811s .' supported on footing foundations may be deveioped in fdctiqn between the foundation bottoms and'the supportinC"f s\.Jbgra·d~.An allowable friction coefficient of 0~30 is considered applicable. An additional allowable passi.ve uniform pres'sure of .500 pounds -13- per square foot acting against the foundations may, be used in design provided the footings are poured neat against the adjacent compacted fill materials or undisturbed natur.al soils. 4. Retaining Halls We recommend that retaining walls be constructed adjacent to the southern and eastern slopes. The southern wall should be sUffie~tly high so as to reduce the slope to a maximum inclination of 2.0 to l. 0, hori zonta 1 to vert; ca 1 uni ts, from top of wa 11 to 'top of slope. The eastern wall should be suffiently high ~o as to reduc~ the slope, inclination to a maximum of 2.0 to 1.0, horizontal to vertical units, from top of wall to the existing gunite ditch. Retaining walls must be designed to resist lateral earth· pressures and any additional lateral loads caused by surcharge loads on the adjoining slab surface. We recommend that ·unrestrained walls be designed for ,an e~~ivalent fluid pressure of 35 pounds per cubi c foot (pcf). He recommerd that res tra i ned, walls be designed for an ~quival~nt fluid pressure of 35 pcf plus an additional uniform lateral pressure of 5H pounds per square foot where H = the height of backfill above the top of the wall footing in feet. Wherever walls will be subjected to surcharge loads, they should also be designed for an additional uniform lateral pressue equal to one-third the an~itipated surcharge pressure in the case of unrestrained walls and one~half the anticipated surcharge in the 'case of restrained walTs. The preceding design pressures assume that there is s~fficient drainage behind the walls to prevent the build-uD of , hydrostatic pressures from surface water infiltration. AdeQuate drainage may be provided by means of weep holes with permeable material installed behind the walls or by means of a system of subdrains'. Backfill placed behind the walls should be compact.ed ,to a minimum degree of compaction of 90 percent using light compaction equipment. -14- • If heavy equipment is used, the walls should be appropriately temporarily braced. Retaining walls should be supported on footing foundations designed in accordance with the reconmendations presented previously under Item 0.1 "Recommendations for Expansive Soils'." Lateral load resistance for the walls can be developed in accordance with the recommendations presented under Item D.3, "Lateral Load Resistance." If you should require any clarffication of the above, don't ~esitate to give us a call. Very truly yours, TORREY PINES CONSULTING Dennis E. Zimmerman, P.E. C26676 DEZ:mh . -15- Dan D. GoOdw,i n Project Manager 'e LIMITATIONS Conclusions and recommendations made in this report are based on the assumption that the soil and geologic conditfons do not deviate apprec~ iably from those disclosed by the test pits. If vari·ations are encountered during construction, TORREY PINES CONSULTING should be nQtifi~d so that we make supplemental recommendations if.this should be required. Evaluation of soil materials for support 'of structures incTudescontinUous inspection during grading. The soil engineer should continue his services through the inspection of grading, including construction of ~}ls, founda- tion eicavations, trench backfill, backfill behind retaining walls and installation of the french drain system. -16- , . " APPENDIX A SUBSURFACE INVESTIGATION The investigation was continuously supervised, excavations logged and samples obtained by this firm for labor~tory testing. Logs of the borings are presented with this appendix. -17- . . EqIJip men! Dimension Test Date 580 C Case B.ackh,oe 24" Auous,t i'2 J9RO Surface Elevation Groundwater Depth " Logged by , Ex.;st;ng Grade 17'6" D.Z. DESCRIPTION a CLASSIFICATION '\H ~ WATER IN-PLACE IC~NE-NT DRY DENSITY , ' DESCRIPTION .,,~, REMARKS COLOR CONSIST. ITYPE SYM. ft. :.r 0/0 pef. -... , C1.ayey fine sand (Fi 11 '-Brown Medi,um SC ~ . : " .. '-Humi,d .:. ~ .... t. iDe,nse, ::' ,'::.: -Clayey fine sand CFnl) Brown !Med SC I':::: ;: ' Moi st ~; .. ~ .::.-f-Dense ....... r', ~ '. : I-I~:; " .:: . . • , !. '" !. : .... : f- i-.:'.: Silty fine sand (Fill) Grey an< Medium SM .;: .: " Mo.i st Orang; s~ Dense .:.,\~ - Brown ':';~:.;: - Mottled , 1. .... ~;.:~.~. -- I-~: : .. : : . ; ....... ~ .... ..... ,,'" : ", : ...... .--.:, '::",'" ........... -t::~;} -7 ... . " .... .. : .... : : ~ ::.~: .. ~:. . I-~ ., .... . :._.::. ••• : i f-·: .. ::.r.;·: "'~'" ....... """ :.:"'::"':-:~ -.: .. ,~~.~ ~;.:~. f -:-10 I'~ "-' . I ....... :,:,~ --•... : :.:. J" " Silty fine sand with cobb1 ~s Light ,r~ed; urn SM I'~':'F:::~' I-Moist (10% to 10") (Fi 11) Brown, Dense t~iH\ f-12· White and -:~:: ::!::. I- Orange f'~'~~~ '1/3. }'ottl eo .' "1 •• ~ --:1 ::;~. ~:~~tura 1 Ground) .:.;:'!.":. -/4 19' ) Light Dense SM '<Z ttom of Trench -.. " t Slightly silty fi'ne sand Brown '. ~: -' Running water, 17' 611 .... V Satura :ed EXPLORATORY TEST Pit .LOG C!OUF.Y fiJlnt.1 COn.iU.Ltin.g ROMERIA STREET CONDOMINIUMS t PROJECT NO. ,DATE LOG· 00051 8-22.,.80 N.O. T1 -18- . Equlpment Dimension Test Date 580 C Case Backhoe 24" August 12, 1980 Surface E/~'~~/c,,; Groundwater Depth L ,',,';',..L>.;.! by-,"'!:n:/"IJ Existing Grade 3' -Su5surf~ce Woter DZ DESCRIPTION a CLASSIFICATION 1\ I WATER IN-PLACE IC~NENT .. DRY DENSITY DESCRIPTION ·"14, REMARKS COLOR CONSIST. ITYPE SYM. ft. E .0/0 pet; .' S1i-ghtly silty-fi:ne sand '.', .', Light Loose ... '" .. S~1 Damp .-.... -· (Natural Ground} Brown . . ' .• : -I:. Sl; Iht1y silty medium sand L i Iht Medium " ',:~:, S~1 Moist ·or ........ f-Brown <to •• " •• , ~ .... :. . . I " f--. , . . .,. .. " .: .. " . r-· : :: :. Clayey fine to medium sand Orange, Dense I:~~$ SC -Satura ~ed with rock (20% to 16") Iron ,0Q~ f- (Free FLowi ng Water) Stai'ns very ~:;: ;:: SM :Slightly sil.!¥. medi'um sand Dens.€. .. .. .. r-· wjth rock (20% to 16") :* ••• ':: .:. .... :'0< .. .. ': '-' ... -.... : t{·; -... 6·~:)· - -!{~.{~{ -Moist . .. I-{~~:q '.... '. ~.~tl .... - :"C}' -16(' -IO~ . ,.I}~ (Near refusal with backhoe f- I .... , f-. 'l· ,Bbttom of Trench -11' 6" :a:: ~ .. :.::". , -I. - -13· - -14· - -15· I- .EX~LORATORY TEST P.lT .~OG C!o'tuy fP£n£.fI. (!onfl.u[t£n9 ~ RDr1ERIA STREET CONDOMINIUMS PROJECT NO. DATE' LOG. 0.0051 8~22-80 NO~ T2 -19-' Equip men! 580 C Case B.ackhoa Surface Elevation Existi"ng Grade Di"1t!7s;or 2.4 II, Groundwdt Depth N/A Tes.t Date Augus,t 12, 1980 Logged by DZ DESCRIPTION a CLASSIFICATION 1\ IH WATER IN-PLACE ICON-DRY TENT DENSITY DESCRIPTION '''~r REMARKS COLOR CONSIST. ITYPE SYM. ft. i= % ' pet "- Sl i ghtly silty nne sand, (F.il U Clayey fine sand, (Fill) (Bottom of Trench = 10 1 ) Light Loose Brown DarR IMedi'um Brown iDens'e- Layered wHir Orangi.sJ Brown S~1 rrn::::~ f-Damp I~: ~.: :.. _ r /_ f- f-/. I- 1-13. f-f4 1-. 1-/5- ~. " , . EXPLORATORY' TEST PIT .LOG ROMERIA 'STREET' coNDOMTNIUr~s PROJECT NO. DATE . LOG, ~---------------4------~----~ 00051 8,..22-8n NO. ' T3 -20- ,..--m;;;;:;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;:;;;;;;;;;;;;:;;;;;;;;;;;;;;;;;;;;;;;;;l Equip men! 580 C Case Backhoe Surface Elevation EXistinq Grade Dimension 24" Groundwater Oepth N/A ' DESCRIPTION a CLASSIFICATION 1\ ~tesi Oot'f/ August 12., 1 980 LogQf1d by DZ WATER IN-PLACE ICON~ .DRY TENT DENSITY DESCRIPTION 'If~,. REMARKS COLOR CONSIST. [TYPE SYM. ·.ft.. ~ % pet. :.;. Slightly silty fine sand, Light (Fill) Brown !) /1 ~ht fy s 11 ty fi ne sand Dark. (F)11) Brown 'Loose Medfum SM Dense Sligh'tly silt fine sand, (Fi 11 ) Orangish Medium SM Grey Mottled Dense Damp Motst Moist EXPLORATORY TEST P·IT .LOG PROJECT NO. 0.00.51 -21- DATE' LOG· NO. T4 Equip men! 580 C Case Back~o~ Surface Elevation Existing Grade Dimension 24 1t' GrVVfluwuter Depth 21 Subsurface Water 'O£SCRIPTION a CLASSIFICATION 1\ 'H Test Date 8:..;l2~8n L';!:I!:Ir:TI.,t, by DZ WATER }N-PL,.ACE CON- TENT DE'NSITY DESCRIPTION H!4,. REMARKS COLOR CONSIST. TYPE SYM. 'ft. ~ 0/0 pct. Slightly silty fine sand, Light Loos e Sr·1;' ":~':. f16i s t .~ .•• I--(Natural Ground) Brown '. I ::'!~: 1--. ' . .. ; ....... Slightly'silty medium sand Light Medium S~,1 ~::'::~ r-_ru_n:....ri __ iin~lg:....w_a_t_er_@_2_' ___ -I-G_r....:ey::....--I-_D_en_s_'e-+_-k:~~ .. ~.\:.;I--. 'Slightly silty fine sand Light Medium SM '*r (Bottom of Trench ~ 91) Brown Dense 1":'-;:1- : .. ~:: ~ : .~~.::. ~ I:·::· .::. - .' ' _: :. ~'. I-- ; ..... :::' roo < .. " .... 1-.: : '.~. I--.. .... :". :: ).::}J-.. ,., .. ~:<::.I--7 " ...... t. ;-.. ,. l- •• tI ... :. :··l.~ ~ ." " ·10" ~ •.... ':t-. ~: : '., -10- '-- I--. 1-12, I- 1-13. 1--/4· I--. 1-'5--. Noist to Satura~ed Noist ~XPLO'RATORY TEST PIT ,LOG Ror1ER.~A STREH· CONDOtWNI1JMS PROJECT NO. DATE O.Q05l -22- LOG, NO. T5 £qulp ment Dlmenslon Test Date 580 C Case Backhoe 2411 August 12,,1980 Surface Elevation Groundwater OeptiJ , Lvyyr;d by Existing Grade N/A ' D.Z., . DESCRIPTION a CLASSIFICATION 1\ .~'~~~:RIN-~~~ti:: ~ ________ ~ __ ~_~_.~~~I~H~· ~ENTDEN~tY OESCRIPTION "'Ur REMARKS COLOR CONSIST. SYM.TYPE :ft .. ~ % .. pcf. Sl i ght1y si 1 ty fine sand Dark Loose ::~~5 SS---~ Damp ~(~'F~iJ~JJ~ ___ ~~-+~B~11r~own-r~~~~'_'Y/' -I~~~-r--~~~--~ C1 ayey fi ne sand (Fi 11 ) \~hi te Medi urn I':: -=-/1 SV i\ Moi s t ~~~ ______________ -r ____ ~~D~ens~;e-¥,.~~~·"~,<,I/~ F-,\~, ____ ~ __ ~ __ ~~~~ Sii.ght1y silty fine sand Grey & Medium .. ':''':'' '- (Fi 11) Orange Dense .:.~:.:. -. ~/~m~ . ~:::3V=3 '\. r-S:::l:'":'i~g h~t'":'l-y -s-:'i 7"lt-y--:"f,:-"' n-e-s-a-n d-:--~L:.J..a':':':.Ye:.!.-'! r~ec--:-:--Hed-:-:' i~u-m +':::~';:'.~::.'~ S C _ "1-:-:~'1:--ol~'·: s""'-:'t-+-----.,.-.,..--+----.....o.-t (Natural Ground) Grey & Dense ; :::,,: (Bottom of Trench -10') I ••• Oral'}ge .. ::':::;' ~\~.::.~ ~: .... <11 ~ ..... ,'\ ."'*,* ',', '''', .~".f. :/. I. ~ '0 • • : to -: .. *. ... .-: > . •• " I 'w~ .', :"'. #.,. ': .. ' ... '''. .,"" 'f .. ' .. -. - -6 -- ~ i"'" --- F- r-, -. -12· -. -13-- :"'14 I- f-IS· i-" • EXPLORATORY TEST Pl-T.LOG "RO!1ERrA S.TREtT CONDO~tNriJnS PROJECT NO. 0.Q0.51 . -23- DATE LOG.· NO. T6: -. APPENDIX B LABORATORY TESTING Sails were classified visually according to the Unified Soil ClaS5~ ification System. Soil classifications are shown on'the Logs of Borings attached to this report. Mechanical analysis, natural densities and moisture contents were performed on representative soil samples. In addition, maximum densities and opti"mum moistures were performed for typical soil materials. Also, the angle of internal fri'ction and cohesion were determined for representative soil samples. Laboratory test results are attached. "-24- " UNIFIED SOIL CLASSIFICATION CHART SOIL DESCRIPTION I. COARSE GRAINED, More than half of material is larger than No. 200 sieve size. GROUP SYHBOL TYPICAL NAMES" GRAVELS CLEAN GRAVELS GW .•.... Well grad~d gravels, g~avel­ sand mixtures, little or no More than half of coarse fraction is larger than No. 4 sieve size but smaller than 3 inches. SANDS More than half of coarse fraction is smaller than No. 4 sieve size. fines. . " GP ..•. ~ . Poorly 'graded gravei s, grave 1- sand mixtures, 1ittle'or no fine' - - - - - - ----- -----'~'~ -. ------ GRAVELS WITH FINES (Appre- ciable amount of fines) GM .•.• ;.Silty gravels', poorly graded gravel~sand-silt·mixtures. GC •.•..• Clayey gravels, PQorly graded gravel-sand-clay mixtures. CLEAN SANDS SW •..... Well graded sa~d, gravelly sahds, , little or'no fines. SP ..•... Pborly graded sands, gravelly , sands, little.or nO fines. -- - - - -------- - -------~ SANDS WITH FINES (Appre- ciable amount of fines) SM •••••• Silty sands,. poorly graded sand-silt mixtures. se .... ~ • Cl ayey s'ands, poorly graded sand-clay ndxtures. II. FINE GRAINED, More than half of material is smaller than No. 200 sieve size. SILTS AND CLAYS r~L •••••• Inorganic 'silts and 'very ftne s.ands, rock flour, 'sandy silt or clayey:"silt-sancl-mixtures with slight plasticity. Liqu.id Limit CL. .••.. Inorganic clays of low tomedjllm less than 50 plasticity, gravelly clays, . sandy clays, silty clays, lean clays.' . OL. .... ~Organic silts and organic silty " € laY,sor.'l ow plasticity. . -25- II. Continued III. HIGHLY ORGANIC SOILS SILTS AND CLAYS . Liqui d Limi t greater than 50 -26- MH .•.••. lnorganic silts, micaceous or di atomaceous fj·ne sandy or silty soils, elastic silts. CH •. ~ ... Inorganic clays of high plasticit fat clays. . OH •.••.• Organi.c clays of medium to high plasticity. PT .•.... Peat and other highly organic soil s. MECHANICAL ANALYSIS Sieve Size 3/8" #4 #8 #16 #30 #50 #100 #200 . TEST RESULTS Tl @ 7.0 1 100.0 99.0 99.7 99.3 97.7 83.3 69.6 55.5 • Percent Passi,ng Sample No. Tl @ 14.0 1 100.0 99.6 99.3 99.0 96.1 79.2 65.6 ~8.7 IN-PLACE DENSITY AND MOISTURE CONTENT BY UNDISTURBED SAMPLE In-Place Density Moisture Content~ Sample (p.c.f.) (Percent of Dry Weight) Tl @ 5.5 1 97.4 19.8 Tl @ 14.0 1 93.8 18.5 EXPANSION TEST Expansion* Sample No. (Percent) Expansion Index T3 @ @ 2.5 1 17.4 174 * Sample tested from ai'r dry moisture content under a surcharge' load of 144 psf. -27- : • OPTIMUM MOISTURE AND MAXIMUM DENSITY RELATIONSHIP Sample No. T1 @ 14.0' ANGLE OF INTERNAL FRICTION, 0 Sample No. T1 @ 5.5 * Assumed from tables. COHESION, C Sample No. Tl @ 5.5 Maximum Density (p.e.f.) 107.2 Optimum Me-i sture (Percent) 1.9.2 Angle of Internal Friction, ~* 10° Cohesion, C (p.s.f.) 250 -28- • • APPENDIX C RECOM~1ENDED GRADING SPECI FICATIONS GENERAL I. It shall be the Contractor's responsibility to place, spread, water and compact the fill in strict ac60rdance with these specifications~ . . A Soils Engineer shall be the Owner's representative to inspect the constructiori of fills. Excavation and the placing of fill s~all be under the direct inspection of the Soils Engineer and he shali give written notice of conformance with the specifications upon completion of grad.ing. Deviations from these specifications will be pennitted " " only upon written authorization from the Soils Engineer. No deviation from these specifications will be allowed, except where specifically superceded in the preliminary soils report,'or in other written communication signed by the Soils Engineer. SCOPE II. The placement of fill by the Contractor shall include all clearing and grubbi.ng, removal of exi sting unsati sfactory' materi a.l, preparation of the areas to be filled, spreading and compaction of fill in the areas to be filled, and all other.work necessary to complete the grading of the filled areas. MATERIALS III. A) Materials for compacted fill shall consi~t of any material "that, in the opinion of the Soils Engineer, is suita~le for use tn construct- ing fills. No material of a perishable, spongy, or unsuitable nature shall be used in filling~ . B) Material placed within 24 inches of rough lot grade shall be select material that swells less than 3% when compacted as hereinafter specified for compacted fill and when subjected to an axial ~ressure of 144 psf. -29- . . • • , C} During grading,operations, soil types other than those analyzed in the report of the soil investigation may be encount- ered by the Contractor. The Soil Engineer shall be consulted to determined the suitability of these. soils. COMPACTED FILLS IV. A) GENERAL L Unless otherwise specified, fill material shall be compacted by the Contractor whi1e·at a moisture content near the Qptimum moisture content and to a density that is not less than .90% of the maximum density determined in accordance with ASTM Test No. 01557-70. 2. Potentially expansive soils may be used in fills ~e10w a, depth of 24 inches and shall be compacted at a moisture content greater than the optimum moisture content for the material. B) CLEARING AND·PREPARING AREAS TO BE FILLED 1. All objectionable material shall be disposed of by, the Contractor. 2. All objectionable material shall be removed by the Contractor from the surface upon which the fill is to be placed and any loose and porous soils shall be removed to the depth specified. The surface shall then be scarified to a minimum depth of 6 inches and recompacted. 3. Where fills are constructed on slopes~ tha Slope of the ~riginal ground on which the fill is to be placed shall be benched and keyed by the Contractor as directed by the Soils Engineer. The benches and keys .sha11 extend completely through the soil mant~e and into the under- lying formation ·materia1s. 4. After the foundation for the, fill has .been cleared and scarified, it shall be compacted as specified for fill. , C) PLACING, SPREADING, AND COMPACTION OF FILL MATERIAL 1. The fill material shall be placed by the Contractor in layers that when compacted shall not exceed 6· inches. Each .layer shall be spread evenly and sh~ll be thoroughly mixed during the spreading to obtain uniformity of material in each layer. -30- • • I 2. When the moisture content of, the fill material is above t~at specified py the Soils Engineer, the fi1l material shall be aerated " by the Contractor by blading, mixing or other satisfactory methods until the moisture content is as specified. 3. ~Jhen the moisture content of the fill material is below, that specified by the Soils Engineer, water shall be added by the Con- tractor until the moisture content is as specified'. 4. After each layer has been placed, mixed and spread even~y, it shall be thoroughly compacted by the Contractor to the specified density. Compaction shall be accomplished by suitable ~ompacting equipment. GRADING CONTROL' V. A) Observations and compactiori tests shall be mad~ by the SoilS Engineer during grading so that he can state that the fill was constructed in accordance with the spcifications. B) The Soils Engineer shall make field density tests in accordance with ASTM Test No. 0-1556-70. When these tests indicate that the density is below the specified density, that portion shall be re- worked until the specified density has been obtained. CONSTRUCTION OBSERVATIONS VI. A) During construction the contractor shall prop~rly grade all excavated surfaces to provide positive drainage and prevent ponding of water. He shall control surface water to avoid damage to ad- joining properties or to finished work on the'site. The.Contractor shall take remedial :measures to prevent erosiOn of freshly graded areas and until such time as permanent drainage and erosion control measures have been installed. B) After completion of grading and the Soils Engineer has finished his observations (j,f the work, no further excavation of filling shall be do~e except under the observation of the Soils EngiDeer. -31- -..