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Home My WebLink AboutCT 14-10; POINSETTIA 61; GEOTECHNICAL REVIEW OF THE MSE WALL PLANS; 2017-08-28• • AGl<CUPOELTA August 28, 2017 Lennar Homes 25 Enterprise, Suite 300 Aliso Viejo, California 92656 Attention: Mr. Jamison Nakaya SUBJECT: GEOTECHNICAL REVIEW OF MSE WALL PLANS Poinsettia 61 Development Carlsbad, california References: Group Delta (2014). Report of Geotechnical Investigation, Poinsettia 61 Mr. Nakaya: Development, Carlsbad, California, Document No. 14-0188, November 20. Group Delta (2017). Supplemental MSE Retaining Wall Recommendations, Poinsettia 61 Development, Carlsbad, California, Document No. 17-0081, July 12. O'Day Consultants (2017). Rough Grading, Storm Drain and Retaining Wall Plans and Details for Poinsettia 61, Sheets 1 through 38, August 21. Soil Retention Designs Inc. (2017A). Verdura Retaining Wall Plans for Poinsettia 61, Sheets 21 through 38, August 18. Soil Retention Designs Inc. (2017B). Verdura Retaining Wall Design Summary and Calculations for Poinsettia 61, SRD Project No. 1704-003, August 21. In accordance with your request, we have reviewed the geotechnical aspects of the referenced Mechanically Stabilized Earth (MSE) retaining wall plans for the Poinsettia 61 Development in Carlsbad, California. We have also conducted global stability analyses for eight cross sections of the planned MSE walls and associated slopes, as shown in the attached figures. In general, our review indicates that the geotechnical aspects of the referenced MSE wall plans conform to the intent of the geotechnical recommendations provided in our supplemental report (GDC, 2017). Specific aspects of the MSE wall plan review and slope stability analyses are discussed below. • ' Geotechnical Review of MSE Wall Plans Poinsettia 61 Development Lennar Homes PLAN REVIEW COMMENTS GDC Project No. SD412B August 28, 2017 Page 2 Group Delta Consultants provided geotechnical recommendations to aid in design of the MSE walls in the referenced letter (GDC, 2017). In summary, we recommended that the existing fill soil in both the retained and foundation influence zones for the new MSE wall be assumed to have a friction angle of 32° with 100 lb/ft2 cohesion, and a total unit weight of about 125 lb/ft3 • Note that the MSE wall design neglected the cohesion component. We also recommended that the soil used in the reinforced zone have a minimum friction angle of 32° with a total unit weight of about 120 lb/ft3• The MSE wall backfill should also be a granular, free draining material with an Expansion Index of 20 or less, and should be compacted to at least 90 percent of the maximum dry unit weight based on ASTM D1557. Our review of Table 3 on Sheet 21 of the MSE wall plans indicates that the MSE wall designer assumed a friction angle of 32° for both the retained and foundation zones, with a unit weight of 125 lb/ft3 for the retained soil, and a unit weight of 120 lb/ft3 for the reinforced zone. These values conform to our recommended soil parameters. Note that the proposed MSE wall backfill should be sampled and tested by Group Delta Consultants prior to placement in order to confirm that these criteria are satisfied. The compacted fill in the reinforced zone should have a friction angle of 32° or more when tested using ASTM D3080 with the test specimens remolded to approximately 90 percent relative compaction per ASTM D1557. The test specimens should be re molded at near optimum moisture content, and then saturated prior to testing. Section 2.05 on Sheet 21 of the MSE wall plans indicates that the soil used in the retained zone should be less than %-inch in maximum dimension, and have no more than 35 percent fines per ASTM D6913. The plans also indicate that the reinforced soil should also have a Plasticity Index (Pl) less than 20 per ASTM D4318, and an Expansion Index less than 20 per ASTM D4829 per our recommendations. Again, soil samples should be tested prior to placement to confirm that the material placed in the reinforced zone meet these criteria. Note that although much of the on- site soil will meet these criteria, the clayey, fine grained soils will not (CL, ML and CH). Table 3 on Sheet 21 of the referenced plans also indicates that a peak ground acceleration (PGA) of 0.30g was applied to the MSE wall design (taken as two-thirds of the PGAM value from the California Building Code). We have no objection to the PGA used for the MSE wall design. GLOBAL STABILITY ANALYSIS The remainder of this document presents the results of our global stability analyses for the planned MSE walls. The general geotechnical conditions throughout the site were described in the referenced investigation report (GDC, 2014). Plan views of the proposed MSE walls and associated slopes are shown in the attached Figures A-1 through H-1 for Cross-Sections A-A' through H-H', respectively (O'Day, 2017). The existing and proposed topography at each cross section location correspond to that shown on the grading plans in Figures A-1 through H-L C~ GROUP DELTA N:\Projects\SD\SD412B Lennar -Poinsettia 61, T&O of Earthwork Construction\5. Reports\17-0100\17-0100.doc • • • • • Geotechnical Review of MSE Wall Plans Poinsettia 61 Development Lennar Homes GDC Project No. 50412B August 28, 2017 Page 3 The proposed MSE wall configuration, geogrid type, and geogrid length at each cross section location correspond to that shown on the Verdura Retaining Wall Plans {Soil Retention, 2017A). The geogrid parameters used for our analyses were summarized in Table 4 on Sheet 21 of the wall plans, and were also summarized in the associated calculations {Soil Retention, 2017B). The planned MSE walls will be located in relatively close proximity to several of the borings and/or test pits conducted for the geotechnical investigation {GDC, 2014). The geologic conditions at each cross section location were estimated based on the conditions encountered in those nearby explorations. Based on the planned depths of excavation, we anticipate that the proposed MSE walls along the northern edge of the site will generally be underlain directly by dense sandstone of the Santiago Formation. However, along the remainder the site {where fills are proposed), the MSE walls will generally be underlain by alluvium that will first need to be excavated and replaced with compacted fill prior to building the planned MSE walls. Maximum temporary cut slope inclinations of 1:1 were recommended for the remedial excavations. However, the saturated alluvium will need to be dewatered prior to excavation . Samples of the various soils encountered in the subsurface explorations were tested as part of the geotechnical investigation, as described in Appendix B of that report {GDC, 2014). Based on those shear tests, we anticipate that compacted fill soils derived from the on-site materials will typically have a drained shear strength exceeding 32° with 100 lb/ft2 cohesion. By comparison, the lower bound of the peak shear strength of the sandstone of the Santiago Formation was estimated as 35° with 150 lb/ft2 cohesion. The shear tests also suggest a lower bound peak strength of 23° with 200 lb/ft2 cohesion for the intact claystone beds, and 19° with zero cohesion for the highly fissured claystone beds encountered in some of the explorations. The referenced MSE wall plans and associated structural calculations included detailed design parameters such as the exposed wall height, wall embedment, wall batter, geogrid type, geogrid length and geogrid locations {Soil Retention, 2017AB). The planned MSE walls will typically have a 1:4 {horizontal to vertical) batter, and will generally use a uniform length of Miragrid SXT, lOXT or 20XT geogrid. The Verdura 40 blocks will typically be about 18-inches wide, 12-inches deep, and 8-inches high. The excavation along the base of each wall will be sloped back beneath the reinforced zone at a minimum 2-percent gradient to a collector subdrain, that will need to outlet to the storm drain system or other approved gravity outlet. The stability of the proposed MSE wall system was evaluated using the program SLOPE/W, incorporating the various soil and geogrid parameters described above. The stability analyses were conducted using Spencer's Method of Slices, which satisfies both force and moment equilibrium. All of the critical failure surfaces were optimized. The analyses focused on the worst-case conditions, including the highest sections of the walls in close proximity to the highest sections of slope. Our stability analyses are presented in the figures immediately following each plan view {i.e. A-2 to A-3 through H-1 to H-4). I;\ ~ GRCLP CELT.A N :\Projects\SD\SD412B Lennar -Poinsettia 61, T&O of Earthwork Construction\5. Reports\17-0100\17-0100.doc • • Geotechnical Review of MSE Wall Plans Poinsettia 61 Development Lennar Homes GDC Project No. 504128 August 28, 2017 Page 4 For each cross section, we evaluated the long-term static stability of the planned MSE wall configuration. Out analyses indicate that the proposed MSE wall sections we analyzed had a long-term Factor of Safety (FS) in excess of the minimum required of 1.5 (FS ~ 1.5). In some cases, we also evaluated the temporary stability of the 1:1 forecuts that will be needed to remove the existing compressible alluvium beneath the development. These analyses indicated that the temporary stability of the 1:1 cut slopes up to 20-feet in height would exceed the minimum required of 1.2 (FS ~ 1.2), provided that the alluvium is first dewatered. For the seismic analyses, we varied the applied pseudo-static horizontal load (Kh) on the wall until the Facor of Safety of the critical failure surface was approximately equal to 1.0 {FS = 1.0). The Yield Acceleration (Ky) determined in this manner was then compared to the Design level Peak Ground Acceleration (PGA) of 0.31g in order to estimate the lateral deformation (!i) that the MSE wall and slope may experience during an earthquake. For most of the sections, the Yield Acceleration exceeded the Design level seismic demand, indicating that no seismic displacement would occur. For the remaining sections, the estimated seismic deformation was less than one inch, which would typically be deemed tolerable per the standards of practice . In summary, our global stability analyses indicate that the planned MSE walls and slopes will have an adequate safety factor against deep seated failure, provided that they are constructed in general accordance with our geotechnical recommendations. The worst-case cross section we analyzed had a long-term safety factor of 1.5, which is typically deemed adequate. Our seismic stability analyses also indicate the MSE walls will experience less than about one inch of lateral deformation due to the Design level earthquake, which is also deemed acceptable. LIMITATIONS Our services were performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable soils engineers and geologists practicing in this or similar localities. No warranty, express or implied, is made as to the conclusions and professional advice included in this report. We appreciate this opportunity to be of professional service. Feel free to contact the office with any questions or comments, or if you need anything else. Senior Geotechnical Engineer Distribution: {1) Addressee, Mr. Mr. Jamison Nakaya (Jamison.Nakaya@Lennar.com) (1) Addressee, Mr. Mr. Andrew Han (andrew.han@lennar.com) lj\ ~ GRCLP CELT.A N:\Projects\SD\SD412B Lennar -Poinsettia 61, T&O of Earthwork Construction\S. Reports\17-0100\17-0100.doc FIGURES A' ----r---165------~"' '-I -260 ''""'-r.i-, ( ( '"°---> V: C( ~ 1·-20· (11x17) \ ,_, ~ ·;,-- DELT .l\ ,-> ~\ ~--- OIIOUP'D6..TACONSULTANTI.INC. "'°-1':C'l'~ EHGINEERSNI> GEQ.OGJSTS 504128 9:245ACTMTYROtiD SUfl'E103 I ~,...-a :::c~.:.CASl212IIM}~1000 17-01()() Poimettia 61 0evek,pmert RGIM. N.IMlf.JI I "'""' Homes A·1 CROSS SECTION A-A' 310 300 290 280 l .'l.11. 5 270 .. .. > ~ w ~T Proposed 12' High Verdura MSE Well Temporary 1:1 Beckcut ., ,':>.,G • !1\ BASIN 3•1 ----------------~ r ------------------.---....,--~-----------------"'------------------ ··----·---···-·--·--·-·-·-------··--------·-IANTIAGO FORMATION (SI', 150 ,.t) 2"0 FILL (3r, 100 psf) (-6, 225) ._.,.1.gll ,~ .... ~~~~ .... ~~~~~--~~~~~~~~~~--~~~~~~~~~~~~~~~~--~~~~~ .... ~~~~--~~~~~--~~~~ ..... ~~~~~--~~~~~--~~~~~~~~~~ 0 10 20 ~ .. .. .. 10 .. .. 100 110 NOTES: The static safety factor for the proposed MSE wall at Section A-P.: does meet the minimum required FS of 1.5 (F.S-2.17). 120 CELTL\ 130 140 OltOl#' OB.TA CONSUL TNrlTI, INC. EHGINE£RS A1C1 GEO..OGISTS 8245 ACTMTY ROIO, SUITE 103 ! ,.:::CAl2t211!5!JW-1000 Poinsettia 61 0."91oprnert Lenrw Homes 150 SD4rn DOQJl4.NI-M 17-0100 ""'l:'r' CROSS SECTION A-A' 310 300 290' I 280 =' * ~ .w g 270 :a .. > ~ 290 200 .... BASIN 3-1 Proposed 12' High Verdul'll MSE Well Tempol'llry 1:1 Beckcut ~ ~•---+--------------------• -~ ----------2 --------------------------------:}#:;; ... ..,..,--.,;;r-;..-----MNT1AGO FORMATION pr, 1N ,-f) -~ ·---... ----·---------------... --·------------. ----...... -......... ----.. --... ----.. -.. ----.......... ----.. ---......._ flfU..(ffl.JOO~ (-6, 225) ~-CIR 10 20 .. ... o ............................................................................................................................ _. ..................................................................................... 1.-................................................................................................ .....1 30 .. .. .. 10 .. 100 110 120 130 140 150 NOTES: The Yield Acceleration (Ky) for the proposed MSE wall at Section A-A' is approximately 0.43g, which exceeds the Design level PGA of 0.31g. The estimated slope deformation under the Design level seismic demand is negligible (less than 1 inch). CELTi\ ~06..TACOHSll..TANTS,NC ~G1--* EHGINEERSANlGE<10GiSTS $04128 924.5 ACTMTY ROH) sum;: 103 J 000 ... oH ~ SANOiEOO CAR'lt211151)US.t000 H-01()() ~, ........ Pwl$ettie 61 OeYelopme,i ~ --Ill ,......., Hornes A-3 CROSS SECTION A·A' . ~ ~ ~ ,. I "' er, "' B r:, ~30S 307.9 304 4 -+---------·----l--~ ~ :fl\, " 303 4 ------------------~ -----;J'Jc."fJRTS" ____ -----\-----~--=-~--==~--~ u~ ~ 1· -20' (11x17) .SOJ.J DELTA I GIIIOI.PDB.TACOHSUl.TANTS,IHC. l"MO.l:CT-11. ENGlNEER$AHO GEa.oGISTS SD412B 9245ACTMTY RCW>. SUITE 10J r DOCU"°'I NUIIKJt ~~==CA8212'IISl)S3&-1000 17-01CX) Poinaettill 61 0e"'81apment -.-_ .. Lerra Homes 8-1 CROSS SECTION B-B' 310 300 290 290 =' al !!::. 5 270 :::, "' > Cl) iii 200 Proposed 22' High Verdura MSE Wall Proposed 9' High Verdura MSE Wall 1&Q • ,..•j c::::::::::1 • I I II I b ~ 240 Temporary 1:1 Backcut FILL (321, 1,»0 '9f) MNT1ACIO FORMATION (35", 150 pett MNT1ACIO FORMATION (35", 150 pett ... ~(-6:·::::22&>~ ...... ~~~~--~~~~~~~~~~~~ ..... ~~~...l....~~~ ....... ~~~---:1~~~~:1:-~~~-=-~~~-::::--~~~::--~~--:::-~~~-;:-~~~"7. 0 - a..,,,a,.,. 10 ,0 30 .. 50 .. 10 .. .. 100 110 120 130 , .. 150 NOTES: The static safety factor for the proposed MSE wall at Section 8-8' does meet the minimum required FS of 1.5 (F.S-1.50). OELT.l\ GAOIM' otl.TACONalJLT.urta. INC. ENGINEERS ANl GEQ..OGISTS V.Z45M:.TMTYROAO,SUlTE 103 PMlLCl-1'1 . SD412B ..:e~~u.mu. i.ll,-10QO 17-0100 Poinsettia 61 De"'91opmen. FIWl'C-11 L&MI Homes B-2 CROSS SECTION B-B' 310 300 290 200 f- =' i !:!:. a 2,0 ,. .. > ., [i ~I .1..QQ PropoHd 22' High Verdura MSE Wall PropoHd 9' High Verdura MSE Wall -- Temporary 1:1 Backcut ---: Fl4" (3i, 1~ 1>9f) 2501 ~~-t I 16 I I 1 1:11:,11 , ~ = l'.J' .... (-6,225) SANTIAGO FORMATION (W, 150 psf) -.... 250'-~~~~--~~~~~~~~~~~~~~~~--~~~~~~~~~~--~~~~~ ..... ~~~~~'-~~~~ ..... ~~~~~ .... ~~~~--~~~~~ .... ~~~~~i....~~~~ ..... ~~~~......1 0 10 20 30 .., 50 .. 10 .. .. 100 ~ The Yield Acceleration (Ky) for the proposed MSE wall at Section 8 -8' is approximately 0.30g. The slope deformation under the Design level seismic demand of 0.31g is estimated at less than 1 inch. 110 120 DELTA 130 1.., OAOU' OELTACONILl.TANTl, INC. EHGINEERSNC> GEQ.OG!STS t24SACTM1'VR0.t0.SU1Tf. '°3 &,A,NOllGO.CA921211158LU,..IOOO "1110JCC::T-f>oinaettia 61 Oe\i181opmert I---Lem1 Homes 150 l"IIIO,LCI ........ SD412B ~ 17-0100 'e:j'' CROSS SECTION B-8' \ ~ ~ 3080 .lOJ.!l 307.9 C' 30~ 304.4 N89:J.J'5.J"W 1~ -+-. --,-_,-..,._ --------- ~ ~:~~~_J ___ _ --= ·~ 3014 ---------------= ---~ -----~~-----= ., -2~~:---~----~~-------~- . ~ 't> 303.J i 29(}---t I '.'5 C .,o,"> ' ~ 1· -20' (11x17) ~ ", CELT.A k f ; ....... DaTACOOISULT""10,0IC. ~"~ ENGINEERSNCIGEQ.OGISTS SD412B 9:24SACT1YITY ROilD SU!'Tf. l03 OOQlt,Ofl -R :::c~.:c CAQ2\2&(8!t)S36-.000 17-0100 Pcinsettie61 Oewk>pmanll ___ .. L8nreHomo• C_:j CROSS SECTION C-C' '10 300 200 2llO Proposed 22' High Verdura MSE Wall Temporary 1:1 Backcut FILL (3r, 100 ~ UlfflAGO FORMATION (W, 111 pat) { ,ro f .=, ! w ,.. ... Proposed 9' High Verdura MSE Wall 8ANTWIO FORMATION (W, 111 psf) (-6, 221) .-.c:,_ -. 0 ---1o 20 .. .. .. .. ro .. .. 100 110 ~ The static safety factor for the proposed MSE wall at Section C-C' does meet the minimum required FS of 1.5 (F.S-1.50). 120 130 140 GROW' Dtt.TACONIUlTAHTl, INC. ENGINEERS ANO GEQ.OGISTS ~5ACTMTYRCW>. SUTE Kil &AHOIECO CAt212'IISl!Sll-tOOO -·-Pomettia 61 OeYetoprnen: Lenna Homes 160 PfllOJECl.....a:ft S0412B 17-0100 'c:'i'' CROSS SECTION C.C' 310 300 I- 200 280 I !:!:. 5 270 l 2tlO ... (-6, 225) Proposed 22' High Verdura MSE Wall Proposed 9' High Verdura MSE Wall Temporary 1:1 Backcut IAN11AGO FORMATION (SP, 111 pef) IAN11AGO FORMATION (SP, 1IO pat) lleclanC2.tllZ , ..... ~~~~~~~~~~~~~~~----~~~~--~~~~~--~~~~--~~~~~--~~~~~--~~~~--~~~~~--~~~~ ...... ~~~~~--~~~~~--~~~~~~~~~~~ 0 10 20 30 .. 50 .. 70 .. .. 100 NOTES: The Yield Acceleration (Ky) for the proposed MSE wall at Section C-C' is approximately 0.31g. The slope defonnalion under the Design level seismic demand of 0.31 g is estimated at less than 1 inch. 110 120 DELT.l\ 1'0 , .. GROtW l>eLTA CONM.ll.TANT&, lllC. ENGINEERSNC> GEa.OOIST$ 924$ ACTMTY Roro surrE 103 150 ~cr~ 504120 ::!c';~ CA1r2t29 ... )5,38.to00 17-0100 Pow'laetlia 61 De"'91op,nef"t O'ICMll[NJ-1'1 Lenne Homos c~ CROSS SECTION C-C' :; ·@) L_ --'--P250.2 I I I I ~ I , ~ I ~ II ~ l : ~----r----,------11 I I I : A4)f 6f71i I I ~~ kf II I :@ :: I P250.6 I I I ,----I I ~ - j __.............1 ~ PR/VA TE STORM ~ 1 n I .:.Q \ ORAIN UN£ if: I I ~v}Y~ _ 5!_£ 9!.E:!_!6_ _ - - -~ \ I I \ I , I \\ ~'o \ \ % ,~ \\ _______ _J <J.B> ~ P251.1 lY~ 12 I I I ~--- ~-1 : ry'l)/ V'(7 v~/ ./ • ,~ r lo / ,1 I I . FG t>-¥ ./ -~ ,, i7:;;. ( . r o·I * ~ N A ~ 1" -20· (11x17) ~ I -~' ----~-- I ~D&..TACOHIULTAHTl,INC. ""°-1:CIM.lla;lt ENGINEERS N«J GEa.OGISTS $04128 9245ACTMTYRO,lr,O&UITE103 I OCIC!JliCNl~ ~ =~.:.:CAl21~!Wi~1000 H-Ql()() Poinsett ill 61 Oew,l,opmen r -~-Lamo Hom>s 0-1 CELT~ CROSS SECTION D-0' ml 270 260~ 250 ¥ t ,.+ ill ., ~ "' iii • 2>o , ·------· Pl ································ • ¥ • ···················································· IANTIAGO FORMATION (JP, 1IO pet) (-6, 11111) ._.,,_ 2000:-~~~~~.~.~~~~~:-:--~~~~~-::--~~~~-:'::'~~~~--::':""~~~~-:::--~~~~~~~~~--:1:-~~~~~~~~~~~~~~~--L~~~~~J..~~~~--.... ~~~~~~~~.:.....J ,. 20 .. .. .. .. 70 .. .. 100 110 120 1,0 140 150 NOTES: Test Pit TP-7 and Boring B-14 indicate thatthere is a considerable amount of loose saturated alluvium in this portion of the site (GDC, 2014). DELTL\ GROlM' DB.TA CONlla.tAHTS, 9'1(:. ENGINEERS AJCJ GEQ..OGISTS 1245ACTMTY ~ SUfT'f 'I03 ~DIEGO CA9212e"'8J5Jl..'!(IO HOil.CT-iii. Poiuettil 61 Oe\18kJpmed lennel-k>mes ~·-504126 ~·~ 17-0100 c:r· CROSS SECTION 0-0' I !!:. ,.T ,ro l 280 250 § 240 1 ., w "30 t Temporary 1:1 Fon1cut ~ 220 •················•······ . ~ ••········••····•········································ 210 SANTIAGO FORMATION (SI', 150 pef) (-6, 1•1 lleclall02.tR 200 ... ~~~~ .... ~~~~~~~~~~~~~~~~~~~~~~ ... ~~~~ .... ~~~~~ .... ~~~~~ .... ~~~~ .... ~~~~~ .... ~~~~--~~~~~--~~~~ ..... ~~~~~--~~~~ ...... 0 10 20 :,0 40 50 .. 10 .. .. 100 NOTES: The alluvium is considered compressible and liquefiable, and should be excavated to expose dense formational materials throughout the site. The safety factor of the proposed temporary 1 :1 cut slope will exceed 1.2, provided that the alluvium is dewatered as necessary. 110 120 DELTL\ 1:,0 140 ~ DEl.l'A COHI\A.lAHTI, INC. ~ANOGEQ.OG!STS 150 ~c,~ SD412B 924SACTMTYR<»D 9UITE 103 ~·-~ CAt2,2t@:5!}536-lOOO 17-01()() "'),.l.:~=-610e...e;opment --~· Leer. Homes 0-3 CROSS SECTION D-D' 280 210 260 .'l..ll 200 ! C ,g 240 ~ FILL (3:Z-, 100 psf) .!! w 230 ------------------------------------. ~ . -----·-·-··---··-··-······-····-··················· 8ANTIAGO FORIIATION (31', 150 pet) (-6, 115) .....,,... 1. 30 10 200.:----------1~0:"'""--------:~:----------~~:---------~-':"'"--------~-:'::""---------_'.'.':""--------~-:---------~-l:----------_.l..--------...l.----------.i..--------...J----------..L.----------.i...----...;;,__J 20 40 IIO 11(1 11(1 .. 100 110 120 130 140 150 NOTES: The static safety factor for the proposed MSE wall at Section D-D' does meet the minimum required FS of 1.5 (F.S-2.12). OELTL\ CftOl.#'08.TACONIULTAHTI, WC. ENGINEERSNC> OEQ..OOlSfS 12,•SACTMTYRo-o SU.Tt: 103 s-,.. DIEGO. e..t.9212'&(1:511 S...t«IO ~~ ?o.nsettia 61 Oevelcpmlri Lenna Homes f'IIOJ[CT-111 SD412B OOO/l,Qfl ....... 111 17-0100 ~04u CROSS SECTION D·D' 280 210 ,.. .w 250 I I I ~ + + ~ l 1 ., ~ 6 240 f I/ FILL (32", 100 psf) ~ > ., iii I y 2lO T•---~ Pl -~ - -------------------. ~ . -------············-····-·-···-·····-··········-···· IWITIAGO FORIIATION (31', 118...,, ,~.115) ......,. ... 200 --~~~~~~~~~~~~~~~~--~~~~--~~~~~ ..... ~~~~--~~~~~--~~~~~--~~~~--~~~~~--~~~~ .... ~~~~~--~~~~~--~~~~--~~~~~• 0 10 20 30 .. so 80 70 .. .. 100 ~ The Yield Acceleration (Ky) for the proposed MSE wall at Section 0-D' is approximately 0.40g, which exceeds the Design level PGAof0.31g. The estimated slope deformation under the Design level seismic demand is negligible (less than 1 inch). 110 120 OELTL\ 1:,0 140 QAou, Dfl.JACOH&la.TAIOS, lilC. EHGiHEfRS NC> GEa..OGISTS Sl2•U ACTMTYRCW>,SUITE ~ SANOIEGO CA9212&(85t)~MIOO H0..1:CI--. Poin9eclia 6 t 0e"8k,prnerj: Lenna Homes 150 SD4i28ft ~ 17-0100 tD:tft CROSS SECTION 0-0' ,-i 1 ., 'l. I , , ~ I ,, I I ,, E' JI I !I ' I , I -I ~ re ~ ~·11 "J-~,r I I I II II / ',,,,v A /"~ 1·-20· (1h17) CELT A EXIST. TDIPQ COITT?EO AG'i TO 8£ R0,10~ Gft(M.IP DfLTACON$1A.TANTl.,91C. "'IO.LCJ~ ENGINEERSAN:>GECl.OGISTS S0412B e24SACTMTYR0iJ\DSU1TE103 ~ .. :C~~ci.irm• w.1000 17-0100 Poraaellil 61 De"'91opmeri --NJ..:; -~ L•""'Homa' E-1 CROSS SECTION E-E' 270 ~t 250 240 .- ..,. l g 230 ~ > Cl) ui ~ • 220 ---~ PL 10 20 30 40 50 eo 10 eo 90 NOTES: Borings B-13 and B-14 indicate that there is a considerable amount of loose saturated alluvium in this portion of the site (GDC, 2014). 100 110 IANTIAOO FORMATION (W, 111 P9f) 120 DELTi\ ~, .... 130 140 Olll(MW DaTACONMJt.TANTI. INC. ENC.NEERSNC> GEQ.00.STS 9245 ACTMTY ~. SUITE 10J !WI OIEOO.CAt:2129115115»-,000 HIO.ECJMK Poinsettia 61 Dewtlopmert Lenra Homes 150 SD4128 ,..,,...,,,_. 17--0100 ~e~R CROSS SECTION E-E' ,ro l 2tlO 250 ,..,_ "" i !:!:. g 230 '" 1 w 220 Pl .Ml! ~--------------------------------------·-------¥ ----···-----···-··---------SANTIAGO FORMATION (31', 19 pef) 10 20 30 .. 30 .. ro .. .. 100 ~ The alluvium is considered compressible and liquefiable, and should be excavated to expose dense formational materials throughout the site. The safety factor of the proposed temporary 1 :1 cut slope will exceed 1.2, provided that the alluvium is dewatered as necessary. 110 120 DELTA 130 leollonE2 .... 140 OA04.P Del.TA CONllA.TAHTa, ltfC. EHGEHE£RSAl'I> OEQ.OGISTS 92.uACTMTY R<W>, ~ 103 130 SD4m ::U°:'~ CAl212tl!lfJ5»-tOOO 17--0100 Poinsettia 6 t Daveklpmert Lenrm tbmea 'E':JR CROSS SECTION E-E' 270 :zeo - 200 240 ! C ~ 230 j w 220 PL Ll!§ • Proposed 8' High Verdura MSE Wall Proposed 8' High Verdura MSE Wall ~ FILL (32", 100 psf) .............................................. ~ ....... IIANTIAOO FORMATION (31', UNI pet) a.dlolEJ.QR 10 20 .. .. 50 .. 10 .. .. 100 110 120 1,0 140 150 NOTES: The static safety factor for the proposed MSE wall at Section E-E' does meet the minimum required FS of 1.5 (F.S-1.88). [ ~~ ~Dfl.TACONSUI.To\HTI.INC. ,,;w::i,u;,~ GRCUP ENGINEERS AHO GEOLOGISTS SD412B -s:~~~12~~':» ~fNJMKlt """°'"'-17-0100 PoinMttil 61 De\1181opmen1 J!CUIE MJ'alt Lema Home• E-4 DELTA CROSS SECTION E-E' 270 ' -~ 250 """ l .1.@ Proposed 8' High Verdure MSE Wall 8 230 ~ .!? w 220 Temporary PL 1:1 Forecut Proposed 8' High Verdure MSE Wall t ALL (32", 100 psf) s:7 .................................................... -----···· ••• .....--......... •••••••••••••••••••••• -MNTIAGO FORMATION (W, 190 p.t) 10 20 30 .. 50 .. 70 00 00 100 NOTES: The Yield Acceleration (Ky) for the proposed MSE wall at Section E-E' is approximately 0.34g, which exceeds the Design level PGA of 0.31g. The estimated slope deformation under the Design level seismic demand is negligible (less than 1 inch). 110 ~ ... 120 130 , .. 150 OltO!JjtOB.TA~TAHTS, .. C. ~Cl-11 EHGINEEMN<I GEQ.OG!STS $04128 1245ACTMTYR<W> SUITE ,00 ~ ~~~ CA9'l12lf151)SJ6.t000 17-0100 floinaett•61 0evelopmenl ~-Ill te""' Hom>, E-5 OELT.l\ CROSS SECTION E-E' ~1 ~o· ,'); ----_...-23 ~i- ~ 1·-20· (11x17) DELTA ' ~ ~TACOHIULTAHTa,IHC. ENGNEERS ~ GE.a..OGJSTS t246ACTMTY~.SIJl11;t0:l ~SAHOEOO. CAl212'f1161)531-t000 ~la610e"'81opmeol Lerra Holl"l&s so:1120· ~lit 17-0100 ""i=::i' CROSS SECTION F-F' 270 290 250 ..- 240 ;' .. .. !=. .Ml § 230 ~ > .. [j 220 21 IANTIAGO FORMATION (W , 150 psf) ~1.goz 10 20 30 40 50 60 70 60 90 100 110 120 130 140 150 NOTES: ~0£t..TACONSU..TANTl,INC. ~CIIMll8Clt I ENGINEERSN<JQE(l._C)GJSTS $04128 124.§ACTMTY ROAD SIJJTE 103 Ooa.,t,oo _-----,;-~= CA 9'l12e ~s»-toOO 17~100 Previous explorations indicate that there is a considerable amount of loose saturated alluvium in this portion of the site (GDC. 2014). Poinsettia 61 0ewtlopmen1 ~ -_R Lenne Homes F-2 CROSS SECTION F-F' 270 280 250 240 ,.,. .. I .. ~ .Mi 5 230 ~ > .. iii 220 21 10 20 30 40 50 80 70 80 90 NOTES: Previous explorations indicate that there is a considerable amount of loose saturated alluvium in this portion of the site (GDC, 2014). 100 110 SANTIAGO FORMATION (31", 190 pet) 120 DELTL\ -1 .... 130 140 ~MLTACONSU.TANTl,INC. ENGIN£ERS AH) CEOLOGlSTS 112'5 ACTMTY RCW> SUfTE 103 SAN_DE00~~'21~~~1000 PMOL<:1"- f>oinsettil 61 Developmen Lenne Homes 150 ~CIMl..-ut SD412B ~·~ 17-0100 F':i"' CROSS SECTION F-F' 270 ""'r 250 , .. I I!:. 5 230 "' .. ~ ilJ =~ 200 190 D NOTES: .-1.H .......................................... 10 20 30 BASIN 4-1 (WITH LINER) / FILL (32", 100 paf) -----------------------------¥-----------~ -··--··· ••••••••• --• • ·····--·-·--··· ••••••••• ·-·· SANTIAGO FORMATION pr, 1S0 pet) 8ecllld2.tllr .. .. .. 70 .. ID 100 ,,. 120 130 1 .. 150 GRou, DEL.TA CON&UlTANTI. .. C. l'fllO..C.CT ~R ENGIHEERSNDGE.O,_OGISTS SD412B The static safety factor for the proposed MSE wall at Section F-F' does meet the minimum required FS of 1.5 (F.S-1.98). IQ,t!j;,t,CTMT'I' ROAD SUITl: ,03 OOCUtiOIT~ ~=~~ CAt2129 531-1000 17-01()() Poinsettia81 ()a"91opmert HQ.#ill-M Lema Homes F-3 DELTL\ CROSS SECTION F-F' 270 2"0 250 ,.. ! C 0 230 l w 220 210· 200 100 .!J)!J_ '---...!..---L BASIN 4-1 (WITH LINER) / FILL (32", 100 psf) --------------------------------· ¥------------------------ -____ -· .•••••• · • ••• •• • -· • · ••• .••• --•• IIANTIAGO FORMATION (W, 111 pet) 0 10 20 .. .., 50 .. 70 .. .. 100 NOTES: The Yield Acceleration (Ky) for the proposed MSE wall at Section F-F' is approximately 0.40g, which exceeds the Design level PGA of 0.31g. The estimated slope deformation under the Design level seismic demand is negligible (less than 1 inch). 110 120 DELT.l\ ._,,,. .... 130 140 OROUPDell'ACONSUI.TANTS.INC. ENGIHEERSNCI GEQ.OGISTS 9245 ACTMTY A<W>, SUITE 103 SANOIEGO.CA82121(161)53&-1000 .. ~CIM..: Poinsettia 61 Developmert lel'Y'IB Homes 150 "'"°'ACl-11 504126 17-0100 'F:i'~ CROSS SECTION F-F' I j l{}j h ~: , , I I ~· I '\.. ® P242.4 ~1~--r-- ,, ', ', ',, "'',,, ' ' ', ', s,~---+-.. ---sr .. --+----J! ',, ' ' ' ', ',, ', ', 2:>8 0 CID P241.5 _____..,240 .......__ _.,..,,.. -.ft---.-... ~I~~ I ............ _ ,, h" /~~· -~---:;-7 / G' ~~~~•. -29, );>-'::::::Jt -;,~ARY ~1/lc tAIRfCT N A V) "' 'P-- J2' / ---- GROUPDn.TACONSUI..TAHTli,~. ""'°-CCf~ EHGINEERSNClGEa.OG!STS S04128 _s:;~™~92~~~~ ~1--0'~ ~ 1 100 Poinsettia 61 Oewttoprnent RGUC....-:9' Lema Homes ~ SCALE: 1·-20· (11x17) DEL T .L\ CROSS SECTION G-G' 310 -1 200 280 ,:::, i ~ ~ 210 .. 1 w 280 250 .~ Proposed 9' High Verdure MSE Wall ~ Temporary 1:1 Backcut ... •1 «:J l11. JL ~ (-6. 221) SANTIAGO FORMATION {U', 1IO psf) -1-230'-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...... ~~~~~ ..... ~~~~ ..... ~~~~ ..... ~~~~~i.-~~~~--~~~~--~~~~ ..... ~~~~~~~~~~~ 0 10 20 .. .. .. .. 10 .. .. 100 110 NOTES: The static safety factor for the proposed MSE wall at Section G-G' does meet the minimum required FS of 1.5 (F.S-2.14). 120 GROUP / DELTL\ 130 ... ~ Del.TACOHSU..TANTl, ltC. ENGINEERS N#J GEOLOGISTS t24SACTM1Y~.SU1TE 103 ~ :::!~CA92t29~)538-1000. I Pcrlsett.111 61 Oevelopmett Lenna Homes 150 """'CfMJ.-;11 SD412B 17-0100 ~:r~ CROSS SECTION G-G' 310 r 300 ... 200 I ,g 270 ! uJ 2t!O 250 I-- .ll)Q Proposed 9' High Verdu111 MSE Wall Tempo111ry 1:1 Backcut 11 -:!II 2401 _._ ..... ____ ,/ IANTIAOO FORMATION (SI", 190..., leclon02-... L.:.:::.=::..... ...... ~~~ ...... ~~~-~~~---~~~ ...... ~~~ ....... ~~~~~~~~~~~~~~--:-::-~~--::~~~-:::-~~-;:;--~~"'7.::~~~-;-: (-6, 2211) .. 50 .. TO .. .. 100 110 120 130 1 .. 150 0 10 20 .. NOTES: The Yield Acceleration (Ky) for the proposed MSE wall at Section G-G' is approximately 0.49g, which exceeds the Design level PGAof 0.31g. The estimated slope deformation under the Design level seismic demand is negligible (less than 1 inch). GROUP l DELT.l\ o;..o:::~~T~e. f S04m ~~~1t2~~':oo ~~!l 17--0100 "1'IO.CCf'4o'lll Poinsettia 61 Devek,pmefi Lel'Yl&Homes 'c;:j' CROSS SECTION G-G' 11 ti i 1 I ;::: I . ! I ·~-@ ·~( I Qg) I ( @ ,1 I p:l P244.8 I P2(M.4 \ \ P244. 1/ : I I 8 I I · ~1·, I i I 1 1 • H I l I I i lt! l:f;l H' 1 , r ~ 1 e: r---,--f----1-1 t------) 1 I v, I I I I ~ J, lb{JN£0 I ,,.., I I ~ I '1 ~ ~ I ::J ~ I I t Cl.. 1 , e5 e I I ~ I Q:: , I ,<i I I ---rT I I ' ' I k ~ I I ~ / I I I . "'"'"i -....!.::-r--;;: ·"" .... : ~ I\ ~ Dl!LTA CONM.l.1AH'TS, 1i1C.. I l.NGlt££RI NC> OEQ.OGISTS l:Z-45 /JCfMT'f ftCW) SUfTt '°3 INIOIEOO CAt212eM1)538-~ l'fU.LCT......:. F>oinaett8610e~ Lerra Homes I _._..__,, SD412B ~"' 17-0100 H:r'' CELT.L\ CROSS SECTION H-H' 280 270 290 250 I- l 5 240 1 G) i~ iii 230 Pl 210 I EXISTING FILL (309, 100 pat) ~ - SANTIAGO FORIIATION (31', 111 pet) 200 INllanH1,8R (-1,115) 100 110 120 130 1 .. 150 0 10 20 30 .. .. .. 10 .. .. ~ Boring B-9 indicates that there is about 8 to 10 feet of existing undocumented fill in this portion of the site (GDC, 2014). Compressible undocumented fill should be excavated and compacted as discussed in Seciton 6.3.2 of the geotechical investigation report (GDC, 2014). CELT.l\ OlllOW' D1!LT4 CONSlA. T.ucta., INC. ENGiHEERS AND GEC..0Gl$TS 824SACTMTY RCW> SUIT1:: 103 ~D1EG0,_CAt:212t~1QOO ~·-Poinsettia 61 OawtkJpfnenl Lenna Homus SD412B oc:a.r..:~ 17-0100 ""WJ"' CROSS SECTION H-H' ... 270 260 250 l C .Q 240 j UJ 230 210 Proposed 8' High Verdura MSE Wall Temporary 1:1 Fonte .ill I EXlSTINO FILL (30", 100 pat) '\ - 1-6.111) FILL (3Z-, 100 paf) UN1WIO FORIIA110N (II', 1N paf) ~ 200 .... ~~~~ .... ~~~~~~~~~~~~~~~~--~~~~~--~~~~~~~~~~--~~~~ .... --~~~~ .... ~~~~~--~~~~--~~~~~--~~~~ .... ~~~~~--~~~~--o 10 20 .. .. so .. 10 .. .. 100 ~ The static safety factor for the proposed MSE wall at Section H-H' does meet the minimum required FS of 1.5 (F.S-1.71). 110 120 DELT.i\ 130 140 CMOf.JtOB.TA~TMTl,NC. ENOIEDtSAJC> Cl:Q.OGISTS f'J45ACTIYIT'(~UTE103 { a......OEOO CA92121fllelJ"8,.IOOO ll"Ml,,liCT""-111[ f)()enaettil61 De¥tl0ptTI6f1 Len,w Homes 150 -.co..-. SD412B ~-,i 17-0100 "ii:j"' CROSS SECTION H-H' 2IO 270 2IO ... ! :s ... ., ~ .. iii ... 210 Proposed 8' High Verduni MSE Wall Temponiry 1:1 Foree ~ .U& I EXISTING FILL (30", 100 pat) :'\ - (-6, 1•1 FILL (32", 100 paf) IAlfflAGO FORIIATION pr, 1N pet) ......., ... 200 L-~~~~~~~~~~~~~--~~~~~~~~~~~~~~~~~~--~~~...i--~~~ ..... ~~~~..i..~~~~.i....~~~ ....... ~~~~~~~~~--~~~--' 0 10 ~ ~ .. 50 .. 70 .. .. 100 110 120 130 140 150 The Yield Acceleration (Ky) for the proposed MSE wall at Section H-H' is approximately 0.34g. The slope deformation under the Design level seismic demand of0.31g is estimated at less than 1 inch. GROUP r ~ ~ ~DII..TACQrllSUL'IA#T&,..C. ll"IIIO.CCJ-..r _,..,.,.,.,.OlOG•STS SD4128 ..:~~il'J~~':oo r-DO:M,UIHUe.lt ~Ct~ 17-0100 PostNbi610e...ec,pm.nt ~ ...,,.......,., H-4 ~ DELTA CROSS SECTION H-H'