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HomeMy WebLinkAbout; La Costa Meadows Unit 1 Lots 190-191; Soils Report; 1983-11-10SOIL RND GEOLOGIC INVESTIGfiTION OF LOTS 19@ T)ND 191 LR COSTFI MEFIDOWS, UNIT 1 CFIRLS!MD, CRLIFORNIQ PREPFIRED FOR: CONWRY RND f%SOCIfiTES, INC. 224 BIRMINGHFJM DRIVE CRRDIFF, CQLIFORNII? 92807 PREPRRED BY; SRN DIEGUITO SOILS, INC. 44@7 MRNCHESTER, SUITE 187 ENCINITCIS, CR 93224 SANDIEGUITOSOILS,INC. 4407 MANCHESTER AVE., SUITE 107 ENCINITAS, CA 92024 (619) 753.8997 SDS 7250 November 10, 1983 Conway and Qssociates, Inc. 224 Birmingham Drive Cat-d if f, CR 92008 nttent ion: Mr. Tim Nagle SOIL 9ND GEOLOGiC INVESTIGATION FOR LOTS ,190 & 191, LFI COSTR MERDOWS, UNIT NO. 1, MFlP NO. 6800, TRFICT 2887-1, CRRLSRFID, CR Dear, Mr. Nagle: We are pleased to Present then results of our soil and geologic investigation for the subJect proJect. This study was performed in accordance with your verbal instructions. The accompanying report presents our cone 1 us i on5 and recommendat ions pertaining to the site, as well as the results of our field explorations and laboratory tests. @W proJect engineer and geologist assigned to this pro;ect were Mr. Zahoor (Ilbbasi and Ms. Linda Cross, respectively. If you have any questions or if we can be of flJrther service to you, please give ~1s a call. Sincerely, SFIN DSEGUITO SOILS, INC., *K- Hill K. Bramble, RCE 8102 Vice-President BKH/ZRR/LC/tll fit t achment s (2) Mr. Rich Masiac (2) Conway & Rssociates (1) Mr. Nar-k Eyerman SDS 7250 TABLE OF CONTENTS SCOPE PURPOSE OF STUDY DESCRIPTION OF PROJECT Page 1 1 FIELD INVESTIGfiTION & LFlPORAfORY TESTS SITE, SOIL, 0ND GEOLOGIC CONDITIONS Site Conditions Overburden Soi 1 s Santiago Peak Volcanics Potential Gealogic Hazards DISCUSSION,~ CONCLUSSIQNS, FlND RECOMMENDRTONS Fa ?I 1 t s Seisnlicfty and Gr,ound Shaking Liquefaction Potential Landslides Groundwater and Surface Drainage Excavation and Soil Characteristics Cut and Fill Slopes Surface PrePar.atictn and Earthwork Foundat ions Retaining Walls and Lateral Loads RISK 9ND OTHER CONSIDERRTIONS PLFlTE 1 SITE PLFIN PLFITES 2 FlND 3 LOGS OF PITS FlPPENDIX f7 LFIBORRTORY TESTS RPPENDIX B GLOSSRRY OF TERMS FI?PENDIX C REFERENCES OPPENDIX D GRFlDING SPECIFICFJTIONS FlPPENDIX E SUHDRF)IN SPECIFICRTIONS - SAN DIEGUITO SOILS, INC. CCiNSULTING GEOTECHMCAL ENG,NEERS 4 -4 4 4 5 5 6 7 7 SAN DIEGUITO SOILS, INC. 4407 MANCHESTER AVE., SUITE 107 ENCINITAS, CA 92024 (619) 753.8997 SDS 7250 November 10, 1’383 SOIL FIND GEOLOGIC INVESTIGpTION FOR LOTS 190 RND 191, Lp COSTR t?EpDOWS, UNIT 1, CRRLSBFID, CXLIFORNIR SCOPE This report presents the results of out’ soil and geological invest’igat ion at the site of the twu mooosed resident ial duplex structures on La Costa. the southeast side of’ Luciernaga Street, PURPOSE OF STUDY The pcwpose of Gur 1 soi 1 conditioris and regarding: nvest igatiori was to evaluate sub-surface to develop data and recomendat ions 1. The geologic setting of the site. 2. Potent ial geologic hazards. 3. Gener*al sub-surface conditions 4. Site grading and earthwork specifications. 5. Types and depths of foundations. 6. pllowable bearing pr‘essures. DESCRIPTION OF PROJECT To aid in our investigation, we have discussed the ProJect with Mr. i’;ar*k Eyerrnan of Mark Eyerrnan and fissociates, Inc. and we have been provided with a topographic map of the site. We understand that the proJect will include grading the site as required and constructing two’ resident ial duplex structures. The residential structures will be of wood frame construct ion and will have split level slab-on-grade concrete f loo,rs, and retaining walls. FIELD INVESTIGRTION FIND LRRORRTORY TESTS Our field investigation was performed on Novernber- 0, 1983 and consisted of mak.ing a visual reconnaissance of existing surface conditions and making four (4) test excavations with a backhoe. Refusal to excavation was encountered at depths ranging from 3 to 5 feet. The approximate locations of the excavations are shown on the attached site plan, Plate 1. The excavations were made under the supervision of a staff geologist from this off ice. Field logs were prepared on the basis of the samples secured and the excavated material. Samples of soils were recovered fr.om the exravat ions and transported to *ur laboratory for visual inspection and testing. The logs of the , borings are presented as Plates 2 and 3. Soils were classified visually accar-d i ng to the Unified Soil Classification System. 0 f dF?esults laborator-y tests are shown at the corresponding sample locat ions CM the lngs and in Flppendix~ Q. SITE, SOIL, FlND GEOLOGIC CONDIT:ONS sike_ Ccmd it i cm5 The subJect prnperty consists uf two lots of roccghiy equal shape and dimensinn fronting on Luciernaga Street. The site siopes gently downward ‘co the north and west. Slopes alung the nco-t her-n property boundary are samewhat -steeper than an the balance of the oroperty. Pm-t ions of the lots have been cleared af vegetation. Other areas are covered with thick low brush. Sum debris and loose fill dirt has been dumped at the site over limited areas as shown on the site plan, Plate 1. Overburden $jls Soil cover at the site is thin to absent. f~ maximum depth of appraximately 8 inches was r:oted in the test excavations. The soil is typically a brown silty clay in a loose condition, containing angular gr,avel and cobble size rock. Sartt iar,g 2_egh Vuleani_cj OUl- geoiugic reconnaissance and fie:d~ invest iga’c ion indicate rJnly one fomlat ional Iunit present on the site. This unit is the Jurassic age Sant iagu Peak. Volcanics. These m i 1 d 1 y met amar*phased volcanic rock.s are slightly to moderately weathered in near-surface and surface exposures and exhibit a COdrSe blocky f ract ure pattern. tSe rocks are increasingly less fractured with depth. Because uf the resistant natilre of these reek+,, numerous c~utcr~c~ps can be forund along the northern and ccntr-ai qnrt icms of the proper-ty. Refusal to excavation with the backhoe was encounfered at relatively shallow depths Over the rest ctf the site as indicated cm the boring logs. potent ial i%c~lnqj& Hazards The pntential geologic hazards of the site were eval@ed cm the basis of a brief geologic reconnaissance of the site and . reviewing the geologic literature including Ecu1 let in 2000, “GjeC*lOgy of the San Diego Metropolitan %ea, California”, published by the California Division of Mines and Geology, the “Seismic Safety Study fur the City of San Diegy”, and “Faults and Epicenters”; prepared by the County of San Diegu. The findinGs are discussed in the following sections of this reclort . DISCUSSION, CONCLUSIONS, RND RECOMMENDRTIONS Faults -----_ No faults or indications of faults were observed during OUP field investigation of the site, nor were’ any identified from 0 ,A,’ review of the “Seismic Safety Study for the City uf San Diego”, Fault Locat ion Map, and the County of San Diego “Faults and Epicenters”. (2) The “Seismic Safety Study for the City of San Dieqo” is limited to the city l’iniits of the City of San Diego, and hence does not cover the site being investigated. However, the northern area of the City of San Dieno is .oniy approximately E miles south of the site and is geolog?cally similar. The area is on a relatively stable plate bounded on the east and west by active faults. The interior of the elate is relatively undisturbed by niaJor faulting. To the west, offshore, is the San Clemente. fault zme. Other s~lcwter fault5 with Holocene displacements are present closer to share, according to Legg. However, to the greater ,confirmed depth, the San Clemente fault zone is considered the r0a.j or bountiar-y fault to the west. On the. east is the San Rndreas system consisting of several fault zones. The San qndreas Fault is 74 miles east of the site. Much of the energy of a maJot* earthquake on this fault would dissipate prior to reaching the site. The Elsinore and San Jarinto fauit zones are closer and likely to have greater impact or, the site. The San Jacinto fault zme is approximately 48 miles east of the site. Maximum probable earth.quakes predicted are on the order of 7.8 on the Richter scale with a 100 year interval ;bkEilen and pinckney, 1372:). The Rose Canyon Fauit iies soluth and west of the site with a postulated uf fshore extension about 8 miles west of the site. The extension parallels the ccast and is suggested by Moore (1972) to connect with the Newport-IngLewood Fault. Thait fault produced the 1333 Long beach earthquake. Thus the inferred potent ial activity for the San Diego area. The maximum credible earthquake anticipated is 7.. 1 Richter magnitude. Recorded seismic activity on the Rose Canyon Fault is low. One short (4-mile long) inferred fault is shown approximately 4. e: miles southeast of the site,- and anot her short (S-mile long) inferred fault is shown approximately 5.5 miles southeast of the site on the County’s Faults and Epicenters Map. These faults are not considered significant to ,the site. Se i sni i ci t y a_& Gr-ound s!~a&jng The San Diego area is within a seismically active region. Both distant and local faults have a potential for earthquake activity. In u u r opinion, the historic record of fault activity is too short to use as a reliable basis fot- defining the potential uf local fault seismicity. R large rnaqnit ude earthquake on the Elsinore Fault or mot-e distant related faults t 0 the east, most notably the San Jacinto .Fault, would likely produce moderate ground shaking at the site. (3) The farther a site is from the epicenter (zone of energy release), the lower the severity of the shaking will be at that point. Local soil conditions and topography tend to modify the nat we and severity of the seismic waves. Ground surface rupture or seismically induced slope failure are not consider-ed likely at this site. Greensfe:der estimates a r~Gximum cr.edible bedrock acceler-at ion on the order of 0.4 times gravity with a predominate period of ?I. 35 seconds for this site. l--gugfautigg Pgtent ial The site is essentiaily on firm soil and bedrock and is not conducive to liquefaction. Lands: ides Nu iandslides were found to underlie the area of proposed grading. Groundwater and Surface Drainage ----------- --- ------- ------ - i n 0 u r apinion, no shallow permanent groundwat er table present iy exists at the site. We recommend that positive measur-es be taken ‘to propen?y finish grade the site after the residences and other ir~?pr~Ve!nsTtS are it-1 qldCe 50 tirat drainage waters are. directed away from the hctuse foundat icws, f 1 oar slabs and tops of slopes. No pondir:g of water in the vicinity of the houses shcauld be Germitted. Even with these provisions, experience has shown that a shallow or surface water condit inn can and may develop irl areas where no such condition existed pr i or t o the site .development ; this is particularly true if there is a substant ial increase in landscape it-rigat ion. &g~~vat_L~~ a_nd_ sei& Characterist its Eased on the results of our test pits, it is our opinion that the stoils on the site can generally be excavated by a light t Cl moderate effort with heavy-duty excavation equipment. However, we expect that excavation of the Santiago Peak Volcanics will require a heavy ripping effort and possible blasting; oversized materiais may result during excavation. Refusal to excavation in scme of the test pits, as well as the existence of roe k UUtCT‘OF)S, indicates areas excavating. Refusal ir, the y,, ‘~~$yth d;;;iy;ati.; equipment used, was encountered at the following depths. Trench No -----.- v-L !keth_ in Ee_& 2 3.5 3 3.0 4 4.0 Refusal i n these excavat inns ~usually indicates either- the presence of large isolated boulders, cw the beginning of the hard rock surface. It is noted, however, that there will be numerous local var,iations in depth of rippability because the hard rock surface is not expected to be uniformly underlying (4) the rippabie materials and should vary in depth f?-orn OWZ location to the next. Therefore it is suggested that considerat ion should be given to the method uf handling and disposing of oversized materials. Cgi; sfid Eill .Siooes We t.ecommend that cut sinpes be 1 l/2:1 or flatter, and fill slooes be indicates 2:l or flatter. Our expe?.ience with similar soils that the pr*ooosed slopes constructed at these slope ratios of on-site materials will have a low probability of deep seated failure fer y sta’ic conditions. Due t 10 ret ura 1 var i at i or6 Of soil strength, however, there is still a finite possibility that the slopes could become unstable. In ofur opinion the probability of the slopes becuming unstable is low. Fill slopes are susceptible to shallow sloughing in periods of rainfall or heavy irrigation. Sloughinp of fill slopes can be reduced by back.roi 1 ing slopes at frequent intervals. FIS a, minimum, we recommend that fill slopes be backroiled at maximum 4-foot fill heirjht intervals. Flddit ional ly, we recommend’ that a?1 --ill slopes be trackwalked so that a dozer track covers all surfaces at least twice. We al50 rec~ommend that ail slnopes be planted, drTainede, and maintained to help control erosiun. Normally, cover-sized hocks (greater t ban 12 inches i n ma x i m u m dimension) can be treated by: (a) removing them from the site; (b) using them as landscape decoration in specified areas; Cc) burying them in predesignated non-str‘uctural fill zones; or Cd) placing them under control ied conditions in str-uct ural f i 11s by comT:etely isolating each bou:der snch that compact ion eq u 1 pment can campact al 1 around each boulder. Ncwmal ly the boulders are kept not less than 4’feet below finish grade and out of the line of pr-oposed utility trenches. Surface Pcepar.at ion _a& Earthwork We recommend that ail existinq fill be removed and replaced and compacted. We recommend that earthwork be done in accor.dance with the attached “Recommended Grading Speci ficat ions.“. San Diegluito Soils, Inc. should observe the grading and test compacted f i ii s. We recommend that a pre-construct ion confe~~ence be held at the site with the developer, civil engineer, contractor, and geotechnical engineer- in attendance. Special soil handling and the grading plans can be disclussed at that time. We recammend that al 1 imported fill soils be approved by this firm at the borrow site. We recommend that al 1 trash, debris, and waste materials be removed from the site before grading. We recommend that al 1 porous topsvoils, slopewash and other ;oose snails be excavated or scarified as required, watered, and then recompact ed prior to placing any additional fill. We (5) recomraeqd that the Soil engineer evaluate the actual depth and extent of excavation and compactic~n in the field at the time af yrading. We recommend that the upper S feet of materials i n the pad areas be cmposed of finish grade, granular- soils. Finish Grade soils are defined as qr*anular soils that have potent ial swell nf iess than 3 percent when recomgacted to 30 percent of maximum laboratory density at opt imum msisture content, placed under an axial load of 150 psf, and soaked in water-. Foundat ions We ~7econ~mer~d that foundat ions on nun-expansive granular 5oi 1 for cane-story portions of the residences, should beg at least 12 i1-tics wide and founded, at not less than 12 inches into properly compacted finish grade soi 1s. Focindat ions of this type may be designed for an allowable soil-bearing pressure of I, 58121 psf total dead-plus-live load. This pressure nmy be i net-eased by one-third fur loads that include wind or seismic’ forces. WE r-ecommend that fcnundat ions on granular soi 1 fsI:- twn-story pc3rt i on5 of the residences sho~uld be at least 15 inches wide and founded r&. less than i8 inches into properTly compacted f inisl, grade soils. Fuundat ions of this type may be designed for an allowable soil-bearinc _ pressure of 2,000 psf total dead- ;J?IJS-: j.ve 1 odd. This pressure may be increased by one-third JOY itoad that include wind co. 5eisraic forces. Rfter the grading is completed, if it is determined that expansive soi is at-e pr,esent within 3 feet nf finish grades, revised foundat ion depths arid bear i ng pressures must be. rccmmended by the soi 1 engineer. We recummend that footings founded in non-expansive granular soil be reinforced top and bottom with at least one No. 4 bar, and the concrete slab-on-grade f lcror be a minirnurn of 4 inches thick and reinforced with 6” x 6 ” , 10/10 welded wire mesh placed at the midpoint of the slab. We recommend that a minimum uf 4-inch underlay of coarse sand and a vaposr barrier be employed. F\fter the grading is completed, if ~lt is determined that expansive soils are present within 3 feet of finish grades, revised slab thickness, reinfnrcement, and construction detail5 must be recommended by the sai 1 engineer-. We recommend that structures not able to tulerate different ial settlements (such as fuundatiuns, concrete decks, walls, etc. ) not be located within 5 feet nf a slope top. We r-eccmm~er~d that footings located within 5 feet from a slope top be extended in depth until that outer b-t v tom edge of the footing is at least 5 feet horizontally from the outside slope face. We recommend that deepened footings founded in non-expansive granular soils be reinforced top and bottom with at least one No. 4 bar. If deepened footings are to be located in expansive soil, revised reinforcement and curlstrmt ior; detai Is must be recommnnded by the s;oi 1 enr;ineer-. I Retainino Walls and Later-al Loads ---_----- ----- --- ------- ----- We recurmend that retaining walls not r-estrained front rnuvenient at the top and required ta supgurt l&et-al earth pressures due to differential soil height be designed fmr an equivalent fluid pressure of 35 pcf. Retaining walls restrained from iooveraent at the top, such as basement or structural Nails, should be designed fur an equivalent fluid presswe of 55 pcf plus a uniform later-al pressure of 189 psf (H = the height af retained earth in feet). These pressures are based cm hurizuntal ground surface cund it ions, the u5e of sandy materials for backfilling~’ the walls, and adequate drainage to prevent bui IdUp of hydrTo-stat ic wess~ure i n t&e backfill. G suggested method of draf?!ace b2S i rid these walIs is presented in t;ie attached Specification f ICI ?’ Sub-surface Drains (Rgperdix E). f f a:nther cnnd i t ions arid /or- particular loads, such as ad Jacent f~cmt ings Cl?’ vehicle sur-charge loads, are to be considered! in tse vicinity of retaining walls, we should be advised 50 that addit ional recoamendat ions can be given as required. Ta provi tie resistance for lateral loads, we ~*ecurmend t:7at passive pressure be assumed equivalmt tn a fluid pressure IGf 400 pcf I>? ;00 pcf fol-. fm:at in25 and s;k,ear- keys fuuu;ded in cut format icmal soils 0 Y‘ pr-o:3er;y compacted fill soils, respect iveiy. The upper 12 inches Gf material in areas rot pmtected by floor- slabs or paven!ents should not be included in design for passive resistance to later-al loads. This lateral pr-essur-e is based on the assumption that the grocnd surface adJacent to the footing is nearly horizontal for a minimum distance nf 10 feet from the face of the footing or three times the height of the surface generat~ing passive pressure, whicheve), is great cr. This design passive earth pres.sure assumes a safety factar of approximately 2 to reduce the rflovermnt s necessary to mobi 1 ize passive resistance. Increased passive resistance may be utilized for seismic loadings if correspm-ldingly lower factclrs of safety .are acceptable. In calculation of frictional resistance to lateral lnads, we recormend using a value of 0.4 as the allowable coeffieisnt Qf sliding frict icm between concrete and the tunderlying mil. If combined frictional and passive lateral t-esistance ar.e utilised in design, the frictiuri coefficient should be b-educed to 0. 3. (7) Backfill placed behind walls should be. compacted to not less than 98% ~of maximum 'dry density using light compaction equi pment. If heavy equipment is used, the walls should be a@proximately braced. RISK FIND DTHZR~COKSIDERFITIONS We have observed oniy a~ small portion of the pertinent soil and groundwater conditions. The recommendat ions made herein are based on the assumption that these conditions do not appreciably krviate fT-Cl;tl t'nose found during our fieid investigation. If the plans for site development are changed, or if variation5 Or‘ undesirable geotechnica! conditions are encountered during construct ion, the. ;eotechnical consultant ‘shou?d be consulted for further recommendations. We recommend that the geotechnical consultant review the foundation and grading plans to verify that the intent of the recommendat ions presented herein has been properly interpreted and incorporated into the contract documents. We further recommend that th@~ oeotechnical consultant observe the site grading, subgrade p&parat i&n unc’er concrete slabs and paved areas, and fo~3-&3t ion excavations. It should also be understood t;hat California, i nc 1 ud i ng San Diego County, is an area of hiCh seismic risk. considered economically urifeasible to It is generally bui Id totai i-y earthguak,e- resistant structures; therefore, it is possible that a large ot‘ nearby earthquake could cause damaGe at the site. Professional .~udrjements presented herein are based part 1 y on 0 u r evai uat ions of the technical infor-rmt ion gathered, partly un 0 II r understanding of the proposed constrluct iun, ard partly 0 n 0 Cl r genera I experience i n the geotechnical field. Cur ens ineering work and Judgemerit rendered meet cut-rent professional standards. We do not guai-antee the performance of the pro.ject in any respect. 'This firm does not practice or consult in the field of safety engineering. We do not direct the contractor's operations, and we cannot be responsible for,the safety of other than our own personne? on the site; therefore, the safety of others is the responsibility of the contractor. The contractor should notify the om-let- if he considetx any of the recommendat ions presented herein to be unsafe. If you have any quest ions regarding this report, please do not hesitate to contact this office. This ~opportuni’ty to be of service is greatly appreciated. Respectfully submitted, SW DIEGUITO SOILS, INC., BILL K. PRFIMBLE, RCE 81OZ - LINDCI CROSS Staff Geologist LOT 147 // COQWAY i, A5500 ATE5 224 Sl133-41t441-i~M De CARDIFF, aa. 11 E?ZJ AREA OF Roclc CXiTcFLOpS --- DEFlhtE5 LJMIT OF LDo5E FILL $ Da3ms (AF-PROn.) V \ I OCATlON: PRFPARFD RY: SAN Dwx.,uT(D Son& 4407 MANwzSTC~ AVE. SUITE 107 ENCIN\-l-AS ) CA. 92024 PHOUE: (619) 753-6497 IdclERN~6.4 5-c Ln COESA, CA. ‘SDS 7250 LOG OF BOFIIN~ SORINGFJO. 1-1 ELEVATION i%Ki~~G undisturbed chunk Loose, dry, brown silty clay,and angular rock CL 1 - \ I n .I. Blocky, weathered metavolcanics with stiff, \' 2, moist brown sandy clay infilling fractures \I, 16.8 97.3. ‘( ', r- 3 - Ifi ."I I- I- , 4 - Excavation difficult at 4.5' on blocky " metavolcanic rock _'I' r, 5 -, Limit of Excavation 5' LOG OF BORING BORING NO. T2 ELEVATION iTiA~%F undisturbed chunk n _ Loose, dry, brown silty clay and gravel 9 5.OM3.5 CL l- 2 - Blocky, metavolcanics, up to 10" size rock. I I- I I ,- \ i.- ! 1 : 1. 2 3 4 ; -i h undisturbed chunk Refusal at 4' hII% 11-8-83 SIJC DIEGIJITO SOIU,‘INC Job No. 7250 ay: T.C Phle No. 3 = UNDISTURBED SAMPLE ‘LOG OFBORING SDS 7250 f2PPENDIX 2 LMIORQTORY TESTS The material5 obser,ved in the test trenches tier-c visGa::y classified and were evaluated with respect t 0 stren~ts, expansive potential, dry density, and mist lure content. -i-se results of thes;e tests are r,epnrtrd below. 1. Field dry density tests were performed us i nn wat et- displacement met hod 0 n wax coated samples to determine the existing cund i t i uns 0 f t 5 e proposed foundation soils. The I-esults of the tests, perfot-med in accordance with accepted engineering practice are a5 follows: Samp 1 e Field Dry Field Moisture ion Locat EEiLY 12_cfl Conte?t (Z) -----L- --_ T-l Ca 1.5 97.3 !6.8 T-2 @ 0.5 103.5 5.0 T-4 e 2.0 105 0 . :4.0 2’. Expan5inn potential of a representative sample of soi: was determined by allowing the sample to s:uell against a surcharge cef 158 psf when brought into contact with water. The expansion 12.P tSe sample frcm the dr-y to satc!rated condition indicates the tested soils are fr.om luw to moderately expansive. The msults 32 f the test are as follows: Samp I e ion iocat T-l 13 1.5 Sample Init ial Cond i t ions ---------- Reinuided to natlural density 3. FI direct shear test was performed stn a sample of soil returned to the laboratory. The test samples were r~emolded to natural density conditions. The results of the test, gerformed in accordance with accepted engineering pract ice are as follows: Sample Densitv Roodrent Fln;r:e of Locat ion ------__ T-2 c6 0.5 Condici& -----Y--- Caheki on QXI~ Tnfppr,:’ Ft.ic’ion :-A-----i ----4--- Remolded to 2E@ 34.5 o field density - SAN DIEGUITO SOILS, INC. CONSULTINGGEOTECHN~CALENG~NEERS APPENDIX B GLOSSARY OF TERMS Acceleration. Rate of change of velocity, felt as an inertia force by objects. Measured here in g's, where l.Og is the acceleration due to gravity. Active Fault. Faults that have had surface displacement within Holocene time (last 11,000 yea~rs) (Hart, 1975). Bedrock. The solid, undisturbed rock in place either at the ground surface or beneath surficial deposits of soil. Cretaceous. The last period of the Mesozoic era (after the Jurassic period and before the Tertiary period of the Cenozoic era). Earthquake Intensity. A measure of the effects of an earthquake at a particular place on humans and/or structures. The intensity at a point depends not only upon the strength of 'the earthquake, or the earthquake magnitude, but also upon the distance from the earthquake to the epicenter and the local geology at the point (Gary, McAfee, and Wolf, 1972). Earthquake Magnitude. A measure of the strength of an earthquake or the strain energy released by it, as determined by seismo- graphic observations. The concept was introduced by the seismologist C. F. Richter, who first applied it to southern' California earthquakes. For that region, he defined local magnitude to logarithm, to the base 10, of the amplitude in microns of the largest trace deflection that would be observed on a standard torsion seismograph (.static magnification = 2,800, period = 0.8 seconds, damping constant = 0.8) at a distance of 100 kilometers from the epicenter. Magnitudes determined at teleseismic distance using the logarithm of the amplitude to period ratio of body waves are called body- wave magnitudes, and using the logarithmof the amplitude of 20-second period surface waves are called surfacewave magnitudes. - SAN DIEGUITO SOILS, INC. CONS"LTlNG GEOSECHNICAL ENGINEERS The local, body-wave and surface-wave magnitudes of an earth- quake will have approximately the same numerical value (Gary McAfee, and Wolf,'l972). Expansive Soil. A soil which has the capability of large volume changes reflecting an increase.or decrease in moisture content. Fault. A surface or zone of rock fracture along which there has been displacement (Gary, McAfee, and Wolf, 1972). Fault Displacement. The dislocation of one side of a fault relative to the other'side resulting from fault movement. Fault Zone. A fault that is expressed as a zone of numerous small fractures or of breccia or fault gouge (Gary, McAfee, and Wolf, 1972). Formation. The basic rock stratigraphic unit in the local classi- fication of rocks, consisting of a body of rock generally characterised by some degree of lithologic homogeneity or ,distinctive lithologic' features, by a prevailingly but not necessarily tabular shape, and by mappability at the Earth's surface. The only formal term that is used for completely dividing the whole geologic column all over the world into named units on the basis of lithology (Gary, McAfee, and Wolf, 1972). Holocene. An epoch of the Quaternary period, from the end of the Pleistocene to the present time, thought to cover the time from approximately 11,000 years ago to the present. Inactive Fault. A Quaternary fault that is determined, from direct evidence, to have become inactive before Holocene time (last 11,000 years) (Hart, 1972). - SANDIEGUITO SOILS, INC CONSVLTING GEOTECHNlCAL ENGlNEERS Jurassic. The second period of the Mesozoic era (after the Triassic and before the Cretaceous periods). Liquefaction. A condition where a soil will undergo continued deformation at a constant low residual stress or with no residual resistance, due to the build-up and maintenance of high pore water pressures which reduce the effective confining pressure to a very low value; pore pressure build-up leading to true liquefaction of this type may be due either to static or cyclic stress applications (Seed, 1976). Potentially Active Faults. Any fault considered to have been active during Quaternary time (last 2 to 3-million ye&s) on the basis of evidence of surface displacement. An exception is a Quaternary fault that is determined, from direct evidence, to have become inactive before Holocene time (last 11,000 years) (Hart, 1972). Sedimentary. Soils formed by the accumulation of layers of elastic and organic material or precipitated salts. Tertiary. The first period of the Cenozoic era (after the Cretaceous of the Mesozoic era and before the Quaternary); thought to span the time between approximately 65-million and 3 million years ago. It is divided into 5 epochs; the Paleocene, Eocene, Oligocene, Miocene and Pliocene. r SAN DIEGUITO SOILS, INC. CONSULTING GEOTECHNICAL ENGINEERS APPENDIX C REFERENCES C.D.M. & G Guidelines No's. 37, 44, 46 and 48 Gary, M., McAfee, R., and Wolf, C.L., eds., 1972, Glossary of Geology; American Geological Institute, Washington, D.C., p. 18, 219, 233, 253, 254, 264, 315, 643, 725-726. Greensfelder, R.W., 1973, A Map of Maximum Expected Bedrock Acceleration from Earthquakes in California: Calif. Div. of Mines and Geol., test, tables, figures, 10 p. Greensfelder, R. W. 1974, "Maximum Credible Rock Acceleration from Earthquakes in California", C.D.M. & G. Map Sheet 23. Hart, Earl W., 1975, Fault Hazard zones in California: California Division of Mines and Geology, Special Publications No. 42. Kennedy, M-P., 1975, Geology of the San Diego metropolitan area, California, Section A, western San Diego metropolitan area; California Division of Mines and Geology, Bulletin 200, 40 p. Legg, M.R. and Kennedy, M.P., 1979, "Faulting Offshore San Diego and Northern Baja California", from Guidebook "Earthquakes and other Perils, San Diego Region" Editor Abbott and Elliott. McEuen, R.B.,and Pinckney, C-J., 1972, Seismic risk in San Diego: San Diego Society of Natural History, Transactions, v. 17, p.33. Moore, G.W., 1972, Offshore extension of the Rose Canyon fault, San Diego, California, in Geological Survey Research, 1972: United States Geological Survey, Professional Paper 800-C, p.113. - SAN DIEGUITO SOILS, INC. CONSULTING GEOTECHNICAL ENGINEERS San Diego County Seismic Safety Element, 1975 Seed, H.B., 1976, Evaluation of soil liquefaction effects on level ground during earthquakes, in Liquefaction Problems in Geotechnical Engineering: American Society of Civil Engineering Annual Convention and Exposition, Philadelphia, Pennsylvania, p. 5. U.S. Department of Agriculture 1973, Soil Survey San Diego Area, California. ,.Weber, F. H., Jr., 1963 Geology and Mineral Resources of San Diego County, California C.D.M.G., County Report 3. Woodward Gizienski b Associates, F Beach Leighton & Associates, 1974, Seismic Safety Study for the City of San Diego. Project 73-279 41 p. - SANDIEGUITO SOILS,INC. CONS"L*lNG GEOTECHNICAL ENGWEERS APPENDIX D 3% RECOMMENDED GRADING SPECIFICATION GENERAL ~INTENT: The intent of these specifications is to establish procedures for clearing, compacting natural ground, preparing areas to be filled and placing and compacting fill soil to the lines and grades shown on the accepted plans. The recommendations contained in the preliminary soil investigation report are a part of the recommended grading specifications and shall supersede the pro- visions contained hereinafter in the case of conflict. INSPECTION AND TESTING A qualifiied soil engineer shall be employed to observe and test the earthwork in accordance with these specifications. It will be necessary that the soil engineer or his representative provide adequate observations so that he may provide a memorandum that the work was or was not accomplished as specified. Deviations from these specifications will be permitted only upon written authori- sation from the soil engineer. It shall be the responsibility of the contractor to assist the soil engineer and to keep him appraised of work schedules, changes and new information and data so that he may provide the memorandum to the owner and govern- mental agency, as required. If, in the opinion of the soil engineer, substandard conditions are encountered, such as questionable soil; poor moisture control, inadequate compaction, adverse weather, etc., the contractor shall stop construction until the conditions are remedied or corrected. Unless otherwise specified, fill material shall be compacted by the contractor while at a moisture content near the optimum moistixe content to a density that is not less than 90% of the maximum dry density determined in accordance with ASTM Test No. D1557-70, or other density test methods that will obtain equiva- 'lent results. CLEARING AND PREPARATICN OF AREAS TO RECEIVE FILL: All trees, brush, grass, and other objectionable material,shall be collected, piled, and burne3 or otherwise disposed of by the contractor so a:; to leave the areas that have been cleared with a neat and finished appearance free from unsightly debris. All vecJet;lble matter and objectionable material shall be removed by the contractor from the surface upon which the fill is to be placed, ancl any loose or porous soils shall be removed or compacted to the depth determined by the soil engineer. The surface shall then be plowed or scarified to a minimum depth of 6 inches until the surface is free from uneven features that would tend to pn vent uniform compaction by Llle equipment to be used. - SANDIEGUITO SOILS, INC. CONSULTING GEOTECHNICAL ENGlNEERS When the slope of the natural ground receiving fill exceeds 20% (5 horizontal to 1 vertical), the original ground shall be stepped or benched as shown on the attached Plate A. Bentihes shall be cut to a firm competent.soil condition. The lower bench shall be at least 10 feet wide and all other benches at least 6 feet wide. Ground slopes flatter than 20% shall be benched when considered necessary by the soil engineer. FILL MATERIAL: Materials for compacted fill shall consist of any material im- ported or excavated from the cut areas that, in the opinion of the soil engineer, is suitable for use.in constructing fills: The material shall contain no rocks or hard lumps greater than 12 inches in size and shall contain at least 40% of material smaller than l/4 inch.in size. (Ma,terials greater than 6 inches ,in size shall be placed by the contractor so that they are sur- rounded by compacted fines; no nesting of rocks shall be per- mitted.) No material of a perishable, spongy, or otherwise im- proper nature shall be used in filling. Material placed within 36 inches of rough grade shall be select material that contains no rocks or hard lumps greater than 6 inches in size and that swells less than3% when compacted as hereinafter specified for compacted fill and soaked under an axial pre,ssure of 150 psf. Potentially expansive soils may be used in fills below a depth of 36 inches and shall be compacted at a moisture content greater than the optimum moisture content for the material. PLACING SPREADING AND COMPACTING OF FILL: Approved material shall be placed in areas prepared to receive fill in layers not to exceed six inches in ccmpacted thickness. Each layer shall have a uniform moisture content in the range that will allow the compaction effort to be efficiently applied to achieve the specified degree of compaction to a minimum specified density with adequately sized equipment, either speci- fically designed for soil compaction or of proven reliability. Compaction.shall be continuous over the entire area, and the equipment shall make sufficient trips to insure that the desired density has been obtained throughout the entire fill. When the moisture content of the fill material is below that specified by the soil engineer, water shall be added by the contractor until the moisture content is as specified. When the moisture content of the fill material is above that specified by the soil engineer, the fill material shall be aerated by the contractor by biaL!ing, mixing, or other satis- factory methods until the moisture content is as specified. a SAN DIEGUITO SOILS,INC. CONSULTlNG GEOTECHNlCAL ENGlNEERS The surface.of fill slopes shall be compacted and there shall be no excess loose soil on the slopes. INSPECTION Observation and compaction tests shall be made by the soil engineer during the fillings and compacting operations so that he can state his opinion that the fill was constructed in accordance with the specifications. The soil engineer shall make field density tests in accordance with ASTM Test No. D 1556-70. Density tests shall be made in the compacted materials below the surface where the surface is disturbed. When these tests indicate that the density of any layer of fill or portion thereof is below the specified density, the particular layer or portion shall be reworked until the specified density has been obtained. The location and frequency of the tests shall be at the soil engineer's discretion. In general, the density tests will be made at an interval not exceeding two feet in vertical rise and/or 500 cubic yards of embankment. PROTECTION OF WORK During construction the contractor shall properly grade all excavated surfaces to provide positive drainage and prevent ponding of water. He shall control surface water to avoid damage to adjoining 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 features have been installed. UNFORSEEN CONDITION: In the event that conditions are encountered during the site preparation and construction that were not encountered during the preliminary soil investigation, San Dieguito Soils, Inc., assumes no responsibility for conditions encountered which differ from those conditions found and described in the pre- liminary soil investigation report. - SAN DIEGUITO SOILS, INC. CONSVLTlNG GEOTECHNICAL ENGNEERS ! I I 1- ,- , > ,.- c RECOMMENDAT IONS FOR FILLING t)N SLOPING GROUND Existing Ground Surface Zone of Loose Surface Soil Compacted Fill Horizontal Benches Into Fismnound, 6 Feet Toe K&y - width To Be Determined By Soil Engineer, But Not Less Than 10 Feet SCHEMATIC ONLY NOT TO SCALE SAN DIEGUITO SOILS INC. PL.AiE A APPENDIX E SPECIFICATION FOR SUBSURFACE DRAINS .- I. DESCRIPTION Subsurface drains consisting of filter gravel or clean gravel enclosed in filter fabric with perforated pipe shall be installed as shown on the plans in accordance with these specifications, unless otherwise specified by the engineer. II. MANUFACTURE Subsurface drain pipe shall be manufactured in accordance with the following requirements. Perforated corrugated ADS pipe shall conform to ASTM Designation F405. Transite underdrain pipe shall conform to ASTM Designation C-508 (Type II). Perforated ABS and PVC pipe shall conform to ASTM Designations 2751 and 3033, respectively, for SDR35; and to ASTM Designations 2661 and 1785, respectively, for SDR 21. The type pipe shall conform to the following table. Material Pipe Maximum Height of Fill (feet) ADS 8 (Corrugated Polyethylene) Transite 'underdrain' 20 PVC or ABS: SDR35 35 SDR21 100 III. FILTER MATERIAL Filter: material for use in backfilling trenches around and over drains shall consist of clean, coarse sand and gravel or crushed stone conforming to the following grading requirements. Sieve Size Percentage Passing Sieve 1" 100 3/4' 90 - 100 3/8" 40 - 100 4 25 - 40 8 18 - 33 30 5- 15 50 o- 7 200 o- 3 - SAN DIEGUITO SOILS, INC. CONSULTlNG GEOTECHNICAL ENGINEERS This material generally conforms with Class II .permeable material in accordance with Section 68-1.025 of the Standard Specifications of the State of California, Department of Transportation. . IV. FILTER FABRIC Filter fabric for use in drains shall consist of Mirafi 140 (Celanese) , Typar (DuPont), or equivalent. The aggregate shall be 3/4-inch to l-l/2-inch maximum size, free draining . aggregate. Filter fabric shall completely surround the aggregate. V. LAYgx .Trenches' for dra'ins shall be excavated to a minimum width of 2 feet. and,to a depth shown on the plans, or as directed by the engineer. The bottom of,the trench ,shall then be covered full width by 4 inches of filter material or with filter fabric and 4 inches of aggregate, and the drain pipe ,shall .be laid with the performations at the bottom and sections shall be joined with couplers.' The pipe shall be laid' on a minimum slope of 0.2 percent and drained to curb outlet or storm drain. After the pipe has been placed, the trench shall be back- filled with filter material of 1-l/2-inch maximum sire aggregate if filter fabric is used to the elevatiqn shown on the plans, or as directed by the engineer. - SAN DIFGJITO SOILS, INC. CONSULTlNG GEOTECHNICAL ENGINEERS