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Home My WebLink AboutCT 97-02; Rancho Carrillo Villages A,B,C,D; Geotechnical Investigation; 1996-06-01ENGINEERING DEPARTMENT SUPPLEMENTAL GEOTECHNICAL INVESTIGATION RANCHO CARRILLO CARLSBAD, CALIFORNIA PREPARED FOR ZONE 18 OWNERS c/o CONTINENTAL HOMES SAN DIEGO, CALIFORNIA RECEIVED Ftcs 1 s ,8 &&& JUNE 1996 Project No. 04787-12-09 June 20, 1996 Zone 18 Owners c/o Continental Homes 12636 High Bluff Drive, Suite 300 San Diego, California 92130 Attention: Mr. David Lother Subject: RANCHO CARRILLO CARLSBAD, CALIFORNIA SUPPLEMENTAL GEOTECHNICAL INVESTIGATION Gentlemen: In accordance with your request and our proposal dated May 9, 1996, we have performed a supplemental geotechnical investigation for the subject project. The purpose of this study was to further investigate three specific areas of proposed cut slopes. The scope of work included additional field exploration, slope stability analyses, and the preparation of this report to provide recommendations regarding the grading of these slopes. In addition, revisions to recommendations presented in the geotechnical reports referenced below are provided. These changes are the result of our review of the grading plans and our response to the geotechnical investigation report review (Geocon Incorporated letter dated June 10, 1996). As part of this supplemental investigation, we have reviewed the following documents: 1. Grading Plans for Rancho Carrillo, (1 inch equals 40 feet), sheets 1 through 51, prepared by Rick Engineering Company, stamp dated May 2, 1996. 2. Preliminary Geotechnical Investigation [for] Rancho Carrillo Villages F, G, L, M, and P, prepared by Geocon Incorporated, dated August 27, 1993. 3. Preliminary Geotechnical Investigation [for] Rancho Carrillo Villages A, B, C, and D, prepared by Geocon Incorporated, dated March 3, 1993. 4. Preliminary Geotechnical Investigation for Rancho Carrillo Villages N, O, Q, R, Tand U, prepared by Geocon Incorporated, dated February 16, 1993. 5. Geotechnical Investigation [for] Rancho Carrillo - Major Roads, prepared by Geocon Incorporated, dated January 15, 1993. Project No. 04787-12-09 June 20, 1996 Page 2 6. Preliminary Geotechnical Investigation [for] Rancho Carrillo Villages E, J and K, prepared by Geocon Incorporated, dated December 30, 1992. 7. Preliminary Geotechnical Investigation [for] Rancho Carrillo, Villages H and I, prepared by Geocon Incorporated, dated The field phase of the investigation consisted of excavating 4 large-diameter borings, downhole logging, and sampling the prevailing materials. Approximate locations of the exploration excavations are shown on Figures 1 through 4. Details of the field exploration is presented in Appendix A. Slope stability analyses for these slopes were performed utilizing the SLOPE/W computer program, based on the Simplified Janbu Method of slices or Simplified Bishop's Method. The analyses are summarized in Appendix B. Design parameters used in the analyses are the same as those used in the referenced reports. 1. CONCLUSIONS AND RECOMMENDATIONS 1.1 Cut Slope — Melrose Avenue Station 117+20 to 121 + 70 1.1.1 Boring Nos. BM-41 and BM-43 were excavated to evaluate the geologic conditions for the planned grading of the 80-foot-high cut slope along the east side of the Melrose Avenue alignment. 1.1.2 Observations at the location of Boring BM-43 indicated the presence of an adversely dipping bedding plane shear at an approximate elevation of 415 feet Mean Sea Level (MSL). Geologic cross-section A-A' is presented on Figure 5. 1.1.3. It is recommended that a drained buttress fill be constructed within the central portion of this slope to mitigate the potential instability of the cut slope. The approximate extent of the buttress fill is shown on Figure 1. Construction should provide for a horizontal shear key width of 40 feet at the bottom. 1.2 Cut Slopes — Southern Margin of Village R 1.2.1 Supplemental exploration (Boring No. BM-42) was performed along the southern property line within Village R to further evaluate remedial grading (see Figure 2). Current mass grading plans show a cut slope with height of 18 to 25 feet. However, the tentative map indicates an ultimate maximum cut slope height of 30 feet. 1.2.2 Observations at the location of the exploratory excavation indicates the presence of a weak clay zone at approximate elevation of 499 feet MSL. As shown on the geologic cross-section B-B' (Figure 6), the weak clay zone is near the elevation of the toe of the cut slope. Project No. 04787-12-09 June 20, 1996 PageS 1.2.3 It is recommended that this potentially adverse geologic condition be mitigated by construction of a drained buttress fill. Grading should provide a minimum shear key width of 25 feet at the bottom. 1.2.4 Off-site residential structures are located in close proximity to the proposed slope. The temporary backcut slope should be no steeper than 1:1 (horizontal to vertical) and should not remain open for an extended period (e.g. over weekends). Grading should be planned to construct the buttress in segments not longer than 200 feet. 1.2.5 It is recommended that this area be instrumented with at least two inclinometers located just behind the top of the slope. Installation should occur prior to starting excavation. Readings will be made during grading to monitor the slope. 1.3 Cut Slopes — Within Northeastern Portion of Village F 1.3.1 The current mass grading plans show nominal grading in this area (Figure 4). However, earlier conceptual grading documents indicated various south- and west- facing cut slopes in this vicinity. 1.3.2 Conditions observed in previous Boring Nos. BP-19 and BP-23, as well as Boring No. BM-44, excavated for this study, indicate interbedding of claystone/siltstone and sandstones with moderate to heavy seepage at the lower depths of exploration. 1.3.3 These geologic conditions may create unsuitable soil moisture problems or surficial instability along proposed cut slopes at this location. Therefore, construction of drained stability fills or toe drains may be required. The final method of mitigation will be based on conditions encountered during the grading operations. 1.4 Shear Key Construction 1.4.1 The original corrective grading to construct Shear Keys Nos. 3 and 4 has been reviewed based on the configuration of the proposed fill slopes as indicated in the tentative map. To accommodate the future grading, it is recommended that these two shear keys be connected by removing the landslide debris between the shear keys in its entirety. Figure 3 shows the modification to the remedial grading as well as the heel drain location. 1.4.2 It is recommended that Shear Key No. 7 be extended to the east to accommodate the future grading of the southeast facing fill slope east of Village R. The revised configuration is shown on Figure 2. 1.4.3 The limits of excavation for grading of Shear Key No. 9 should be extended to remove minor portions of the existing landslide. This will provide stability of the temporary backcut. Figure 1 shows the revised configuration. Project No. 04787-12-09 June 20, 1996 Page 4 1.5 Miscellaneous Recommendation Modifications 1.5.1 Where lots are underlain by highly expansive soils (Expansion Index greater than 90) the undercutting of pads should be increased from 3 feet to 4 feet and the pads capped with select soils. 1.5.2 The undercut portion of transition lots should be sloped toward the fill portion to reduce the potential for accumulation of irrigation and nuisance water. 1.5.3 The last 20 feet of subdrains should consist of solid (nonperforated) pipe separated from the perforated pipe by a concrete cutoff wall. Solid pipe should also be used where a subdrain crosses through a fill area. 1.5.4 Subdrain cleanouts as recommended in the original geotechnical reports are not required. If you have any questions regarding this supplemental report, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GE0CON INCO RCE 2252 AS:DFL:dmc (6) Addressee (1) Ladwig Design Group, Inc. Attention: Mr. Bob Ladwig (2) Rick Engineering Company Attention: Mr. Craig Kahlen (2) Scripps Hospital c/o James Leary Architects Attention: Mr. James Leary (2) UDC Homes Attention; Mr. Dennis Ferdig (2) Woodward/Merrill Lynch Assets Recovery Management Attention: Mr. Bernie May RANCHO CARRILLO CARLSBAD, CALIFORNIA N SCALE: 1" = 100' LEGEND '. UNDOCUMENTED FILL ALLUVIUM QIS LANDSLIDE DEBRIS Td DELMAR FORMATION SHEAR KEY s SUBDRAIN INCORPORATED GEOTECHNICAL ENGINEERS AND ENGINEERING GEOLOGISTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121-2974 PHONE 619 55S-6900 - FAX 619 55S-6159 PROJECT NO. 04787-12-09 FIGURE I DATE 06-20-1996 RANCHO CARRILLO CARLSBAD, CALIFORNIA <v GEOCON INCORPORATED kl GEOTECHNICAL ENGINEERS AND ENGINEERING GEOLOGISTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121-2974 PHONE 619 558-6900 - FAX 619 55S-6159 PROJECT NO. 04787-12-09 RGURE 2 DATE 06-26-1996 RANCHO CARRILLO CARLSBAD, CALIFORNIA GEOCON INCORPORATED GEOTECHNICAL ENGINEERS AND ENGINEERING GEOLOGISTS 6%0 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121-2974 PHONE 619 55S-6900 - FAX 619 55S-6159 PROJECT NO. 04787-12-09 FIGURE 3 DATE 06-20-1996 RANCHO CARRILLO CARLSBAD, CALIFORNIA GEOCON INCORPORATED GEOTECHNICAL ENGINEERS AND ENGINEERING GEOLOGISTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121-2974 PHONE 619 558-6900 - FAX 619 55J-6159 PROJECT NO. 04787-12-09 FIGURE 4 DATE 06-20-1996 SCALE: i" = 40' (HORIZ.= VERT.) RANCHO CARRILLO CARLSBAD, CALIFORNIA A EXISTING GROUND SURFACE PROPOSED GRADE 460-1 MELROSE AVE. STA.II8+65 420- 380 -i A1 BEDDING PLANE SHEAR f-SOO L-460 — 420 -380 -340340-1 7C/ UNDOCUMENTED FILL ALLUVIUM LANDSLIDE DEBRIS DELMAR FORMATION CROSS-SECTION A-A' GEOCON INCORPORATED GEOTECHNICAL ENGINEERS AND ENGINEERING GEOLOGISTS 6960 FLANDERS DRIVE - SAN DIEGO. CALIFORNIA 92121-2974 PHONE 619 558-6900 - FAX 619 55S-6159 PROJECT NO. 04787-12-09 FIGURE 5 DATE 6-20-1996 B 580 H 54O- 500- 460- 42O-I BUILDING TEMPORARY SLOPE PROPOSED GRADE B r500 -460 1-420 SCALE: i" = 4o'(HORiz.= RANCHO CARRILLO CARLSBAD, CALIFORNIA CROSS-SECTION B-B1 GEOCON INCORPORATED GEOTECHNICAL ENGINEERS AND ENGINEERING GEOLOGISTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121-2974 PHONE 619 558-6900 - FAX 619 55S-6159 PROJECT NO. 04787-12-09 FIGURE 6 DATE 6-2O-1996 APPENDIX Project No. 04787-12-09 June 20, 1996 APPENDIX A FIELD INVESTIGATION •«• The field investigation was performed on May 21 and 22, 1996, and consisted of the excavation •«• m of 4 large-diameter exploratory borings. The depths of excavation ranged from 45 to 83 feet * below existing ground surface. The location of the exploratory borings are shown on Figures 1 through 4. As drilling for each boring was completed, the excavation was visually classified and down-hole logged by an engineering geologist. ** The exploratory borings were excavated by a truck-mounted E-120 drill rig with a 30-inch- diameter bucket-auger. As drilling proceeded, relatively undisturbed drive samples and Ml disturbed bulk samples were obtained at various depths in the borings and returned to our ** laboratory for testing. The relatively undisturbed samples were obtained by driving a 3-inch, "Sttft outside diameter, split-tube sampler into undisturbed soil mass with blows from the Kelly bar*•» falling 12 inches. Logs of the borings are presented on Figure A-l through A-10. PROJECT NO. 04787-12-09 DEPTH IN FEET AU - 2 - - 4 - - 6 - - 8 - - 10 - - 12 - - 14 - - 16 - 1 Q18 - 20 - - 22 — - 24 - - 26 - - 28 - SAMPLE NO. LI T H O L O G Y /j/V/vy % $ ft f / MM, mil \ %1 [| GR O U N D W A T E R :f: ['• 1 1 — '//II%%A/ ff ? \~t; [:ti [: [: SOIL CLASS (USCS) CL ML SM/ML ML CL/ML SM BORING BM41 ELEV. (MSL.) 488 DATE COMPLETED 5/21/96 EQUIPMENT E-120 MATERIAL DESCRIPTION TOPSOIL Stiff, moist, brown, Silty CLAY DELMAR FORMATION Very dense, damp light green to medium green, SILTSTONE; thinly bedded with calcium carbonate along bedding planes, near horizontal bedding -Becomes olive brown, Sandy, and fossiliferous at 5.8 feet -Highly cemented concretionary bed from 7.7 to 9 feet; difficult drilling Dense, damp, light grey, Silty fine SANDSTONE to fine Sandy SILTSTONE Dense, damp, medium green, Clayey SILTSTONE; variable clay content -Bedding Plane Shear at 14.8 feet (Near horizontal); 1/8" to 1/4" thick -Becomes moist, greyish green, remolded plastic clay, continuous but poorly remolded, irregular thickness and slightly undulatory -Bedding Plane Shear at 16.2 feet (Near horizontal): 2 inch thick - l ( -Zone of thin moist subparallel planes, continuous but i \ poorly remolded ' Hard, damp, greyish green, Silty CLAYSTONE/Clayey SILTSTONE -Bedding Plane Shear at 20 feet (Near horizontal); 1/8" to 1/4" thick, moist, greyish green, remolded plastic clay, continuous and moderately remolded -Bedding Plane Shear at 22.3 feet (Near horizontal); 1/8" to 2" thick, moist, blue green, remolded plastic , , clay, continuous and well developed, irregular ' i thickness J 1 -Bedding Plane Shear at 23.5 feet (Near ' i horizontal); 1/4" to 1" thick, moist, blue green, J i remolded plastic clay, continuous and well developed, i i irregular thickness ' Dense, damp, orange brown, Silty, fine to coarse SANDSTONE; zones of low cohesive sands PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) - - - - - - - a MO I S T U R E CO N T E N T < X ) Figure A-l Log of Boring BM 41, page 1 of 3 RC09 SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL C ... STANDARD PENETRATION TEST • H ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE 5P DRIVE SAMPLE (UNDISTURBED) WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. PROJECT NO. 04787-12-09 DEPTH IN FEET o/-\3D _ ^fj - 34 - - 36 - - 38 - - 40 - - - 42 - - 44 - - 46 - - 48 - - 50 - - 52 - - 54 - - 56 - - 58 - ** c SAMPLE c NO. f :'[•' ^ JM41-1 '•-.- JM41-2 > / '/ / 6 / , ' ' >, :> JM41-3 >, JM41-4 X '/ QL \ n U L U L ) T JN D W A T E H OJ CC CD S3:x x• / ' '' -' • •' • / , /' / • ' , , ;v >, SOIL CLASS (USCS) ML TT% ^VT* TIVT/^ Tilt yl" /HBORING BM 41 ELEV. (MSL.) 488 DATE COMPLETED 5/21/96 EQUIPMENT E-120 MATERIAL DESCRIPTION -One foot thick concretionary bed at 25 feet, several * concretions trom 2o to 30 leet Dense, damp, medium green, Clayey SILTSTONE; thinly laminated -Becomes light grey /green and massive with a decrease in clay content at 35 feet -Concretional bed from 39.5 to 40.5 feet •R A T I O N ST A N C E IS / F T . ) f~ UJ-*LUf^O 2m-lujy«QQ.^^ 6 - - - - - - - - - s-iu: WuQ . 5-d. K~Q ^iu5*£K ^h-Wm. i UJ Q1"gzEou Figure A-2 Log of Boring BM 41, page 2 of 3 RC09 SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL H ... DISTURBED OR BAG SAMPLE C... STANDARD PENETRATION TEST B ... CHUNK SAMPLE ... DRIVE SAMPLE (UNDISTURBED) ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. PROJECT NO. 04787-12-09 DEPTH IN FEET oO n - 62 -| - 64 -1 - 66 - - 68 - - 70 - 12. - 74 - - 76 - noto SAMPLE NO. JM41-5 JM41-6 1 1 i 5(r fh :£ .V » r:& *»K ''\'' :t /, / ,,', ''' , :;: 1—T1 3: Hj i|. s[ ii • f '/ f' / /' ceLU /T" Q 0CCCO SOIL CLASS (USCS) SM/ML ML/CL ML BORING BM 41 ELEV. (MSL.) 488 DATE COMPLETED 5/21/96 EQUIPMENT E-120 MATERIAL DESCRIPTION Dense, damp, light grey to light brown, Silty fine SANDSTONE/fme Sandy SILTSTONE - Dense, damp, reddish brown, Clayey SILTSTONE/ Silty CLAYSTONE, thinly laminated Very dense, damp, dark grey, Clayey SILTSTONE; well cemented BORING TERMINATED AT 78 FEET SLJ^<•_* fjHftZ [ . Mpi LU^CQ 20 5- ' /">!, UCJ^ * cz^Q ~ ||| "• fe M^Eg CJ Figure A-3 Log of Boring BM 41, page 3 of 3 RC09 SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL H ... DISTURBED OR BAG SAMPLE C... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED) B ... CHUNK SAMPLE I ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. PROJECT NO. 04787-12-09 DEPTH IN FEET - A0 ~ - 4 - " - 6 - o8 ~ - 10 - _ - 12 - - 14 - - — 16 - 18 - - - 20 - - - 22 - - 24 - - - 26 - - 28 - SAMPLE NO. JM42-1 JM42-2 1 1 i CDo O h- H "1 ' 1 T- 1-, 1 1 :£$: •&iH' $j$ i-^vi If -'f:-'-t' H'!jvl ',''[' ',['. •Yily:'-3':: :>ty:f::£k[: vXv •*p**"*t* IyJ<N\Ml*l* :$]?: :£J^:*..%*.* **[*K^'*vJ*X ':[:•:£ :£•:[: **M**t*IvKrI |;j| || QLU 3Q Z)Oo:CD SOIL CLASS (USCS) SM SM/ML SM T*/"VT*TTWT/^1 T»Tl If A^BORING BM 42 ELEV. (MSL.) 534 DATE COMPLETED 5/21/96 EQUIPMENT E-120 MATERIAL DESCRIPTION FILL Medium dense, damp, light grey, Silty, fine to ^ medium SAND DELMAR FORMATION Dense, damp, light grey with orange mottling, Silty fine SANDSTONE/fine Sandy SILTSTONE -Several high angle clay filled fractures up to 1/8" thick from 5 to 8 feet Gradational contact r Dense, damp to moist, light brown, Silty, fine to medium SANDSTONE with little clay -3/4" thick semi-continuous green weathered claystone bed enveloped in a 4" thick marlaceous lens at 10.5 feet -Irregular shaped fossiliferous concretionary bed from 11 to 12 feet -Becomes slightly fractured and blocky at 12 feet; zones of small green clay ripup clasts -Joint at 13 feet; N34E, 82SE, some rootlets along fracture -CLAY contender decreases at 13 feet, zones of low cohesion -Moderately jointed at 17 feet -Joint at 17.5 feet; N58W, 87SW, roots growing along joint -Near vertical approx. east- west trending, closed fracture from 20 to 22 feet; thin orange near horizontal bedding is truncated by fracture and down dropped approx. one inch on south side -Near vertical, approx. east- west trending closed fracture from 23.5 to 26 feet; thin bedding truncated and down dropped approx. 1 inch on south side, several subparallel fractures, thin bedding N42W.14SW §a"H _ i— h-^j-UL . yj «_ ill •* t^zftfj Q.tt:w 4_ — _ - - - - - - £^ H f**)\ l_ (Soo . >£ Q /^ LU-5 *~|) cn2 t_ if^Jg| o Figure A-4 Log of Boring BM 42, page 1 of 2 RC09 SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C... STANDARD PENETRATION TEST H... DRIVE SAMPLE (UNDISTURBED) H ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE T. ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. PROJECT NO. 04787-12-09 DEPTH IN FEET 30 - 32 - - 34 - - 36 - - 38 - - 40 - - 42 - - 44 - SAMPLE NO.TH O L O G Y H ;$£.vKr.'/%%&mII 111 I cc UN D W A T E 0ceCD SOIL CLASS (USCS) SM CL/ML SC/SM T»/'"\T»TXT/~1 T»T\ yf y*-^BORING BM 42 ELEV. (MSL.) 534 DATE COMPLETED 5/21/96 EQUIPMENT E-120 MATERIAL DESCRIPTION -Becomes fine to coarse and orange color at 30 feet * -Irregular near horizontal contact Hard, damp, medium to dark green, Silty CLAYSTONE/ Clayey SILTSTONE -Becomes waxy and blocky with weak appearance at 34 feet -Thinly laminated with moist planes along laminations at 34.5 feet Poorly developed -Bedding Plane Shear at 35.4 feet (Near horizontal); i 1/16" to 1/8" thick slightly remolded blue green '1 CLAY in 3/4 of boring, undulatory , i -Cemented fossiliferous concretion from 37.5 to 38.5 j i feet ' Dense, damp, olive brown, Silty/Clayey, fine to coarse SANDSTONE with abundant cemented concretionary zones; abundant shells BORING TERMINATED AT 45 FEET °u~ LLlJflO o_a-\^ LUJ >i Q S^i LU ^o:si a Figure A-5 Log of Boring BM 42, page 2 of 2 RC09 SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL B... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED) H ... DISTURBED OR BAG SAMPLE U ... CHUNK SAMPLE T_ ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. PROJECT NO. 04787-12-09 DEPTH IN FEET AU - 2 - - 4 - - 6 - - 8 - - 10 - - 12 - — - 14 - - - 16 - - 18 - - 20 - - 22 - - 24 - - 26 - - 28 - - SAMPLE NO. '/- /_ <[ j:| ijt *,f V :% !;[ li ijt V ':[ | | JM43-1 •:« JM43-2 |:j| •: CfL> LUCD 1 —n IT _l 3O Q f— OH O_l QLCD X _ /'/ /:/ :]:?: :]:| 1^' * r*•]•:: :i::: :^:V : :¥ ::•[: * "*t* $:[: :| :| fit: |3j| il || -1 SOIL CLASS (USCS) SC SM ML SM ML T*/™VT"*TTWT/~'1 T*H X A^BORING BM 43 ELEV. (MSL.) 460 DATE COMPLETED 5/21/96 EQUIPMENT E-120 MATERIAL DESCRIPTION TOPSOIL Medium dense, damp, brown, Clayey, fine to medium SAND DELMAR FORMATION Dense, damp, orange brown, Silty fine SANDSTONE x Gradational contact Dense, damp, light green, SILTSTONE with little clay; thinly laminated with orange oxide along laminations 'v -Gradational contact f Dense, damp, orange brown, Silty fine SANDSTONE; massive -Distinct cross-bedding/bedding at 15 feet; 12 degree;N80W -Becomes light grey in color at 15 feet Dense, damp, light grey to light green, SILTSTONE; Z s^o y • 1 ^. I .<c*^\ 11 HF^ Lu^mQ.0^ - 5 - - - - > M- CO ' ad Q ^>!b a ^^ ui;5ce jj£ [— jj^J Eg u Figure A-6 Log of Boring BM 43, page 1 of 3 RC09 SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL H ... DISTURBED OR BAG SAMPLE C ... STANDARD PENETRATION TEST B ... CHUNK SAMPLE ... DRIVE SAMPLE (UNDISTURBED) ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. PROJECT NO. 04787-12-09 DEPTH IN FEET 30 - - 32 - - 34 - - 36 - - 38 - - 40 - - 42 - . - 44 - - 46 - - - 48 ~ — - 50 - - 52 - - - 54 - - 56 - - 58 - — SAMPLE NO. JM43-3 JM43-4 >CIc 3H 1- 1 1 1 1 J I 1 1 1* '*•:k- a:LU> i—i ^J 3! a 1 OJ CCCD •y:•• SOIL CLASS (USCS) ML SM T1/"\T"*TTVT/"~'1 Till /W A^BORING BM 43 ELEV. (MSL.) 460 DATE COMPLETED 5/21/96 EQUIPMENT E-120 MATERIAL DESCRIPTION some Clayey SILTSTONE zones, thinly laminated abundant gypsum veinlets along laminations -Grades to zones of fine Sandy SILTSTONE below 30 feet -One foot thick, highly cemented, fossiliferous concretionary bed at 42.5 feet -Zone of multiple -Bedding Plane Shears at 44.8 feet (7 degree;S85W); Shearing is accomodated on several subparallel continuous planes well developed around boring moist, greyish green plastic clay is variable thickness from 1/8" to 1/2" thick, poorly remolded in areas -6 inch thick fossiliferous concretionary bed at 45.5 feet -Reddish brown, Clayey SILTSTONE lens from 53 to 56 feet \ Gradational contact /" Dense, damp, liaht 2rev to oranue brown. Siltv fine giii^ «z ol^w HI 1—4^ ui^mQ-0-^ - _ - - - - - — 20 - - >- • "^^ rH . WdLJ . >i Q /-. LLl^5UNi_jLU °| CJ Figure A-7 Log of Boring BM 43, page 2 of 3 RC09 SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL H ... DISTURBED OR BAG SAMPLE C... STANDARD PENETRATION TEST E ... CHUNK SAMPLE DRIVE SAMPLE (UNDISTURBED) WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. PROJECT NO. 04787-12-09 DEPTH IN FEET 60 - 62 - - 64 - - 66 - - — 60 in/u - 72 - - 74 - - 76 - - 78 - - 80 - - - 82 - SAMPLE NO. I * . ' • , / / ' ' ' - , , , > >-CDo O H -1 [::• h '*'t /. r V v K ^£°IKI \: $fyM< '.• ' • ;. . , 9 t 9 ' / ' / / :';• ,'''', * ', f' / ' ' /' / * V ' QLLUh— a occCD • * • • ^// ' , ' * > * SOIL CLASS (USCS) SM CL/ML SM ML BORING BM 43 ELEV. (MSL.) 460 DATE COMPLETED 5/21/96 EQUIPMENT E-120 MATERIAL DESCRIPTION SANDSTONE -One foot thick concretionary bed at 63 feet, difficult drilling Hard, damp, reddish-brown, Silty CLAYSTONE/Clayey SILTSTONE; thinly laminated, gypsum veinlets along laminations Dense, damp, orange, fossiliferous SANDSTONE -Six inch thick concretionary bed at 70.2 feet Very dense, damp, dark grey to black, Clayey SILTSTONE; zone of silty claystone -Down hole logging terminated at 80 feet due to sloughage BORING TERMINATED AT 83 FEET ~z. ^->,og . l~?u- i""jHp5 Lu^m Q.'^w ~ L - " - - - - - -j_\~ f^ &Q ~ QL^1=1 s^ MJ*^ ^2 1— iti] gg CJ Figure A-8 Log of Boring BM 43, page 3 of 3 RC09 SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL E ... STANDARD PENETRATION TEST • ... DRIVE SAMPLE (UNDISTURBED) H ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE I ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. PROJECT NO. 04787-12-09 DEPTH IN CCCTrbb [ nU - 2 - - 4 - - 6 - - o~ 8 - _ - 10 - - 12 - - 14 - — - 16 - ~ - 18 - - 20 - _ - 22 - - 24 -}_ - 26 - - 28 - SAMPLE NO. JM44-1 JM44-2 — .1 ! 1s CDO oI H -1 '/ ' / /• / /../ / - / /:/ & wit v/yy/yY/VA/%' y%7/% Y$%7 Y%%% v0y/fr yx/X%/'/M/M6 y%s/% :y|:[ :£vt '"tyifi I*M*V:::i::l X*3v wtvt|!fm<f>t[ •t\jX *'tv»[ •*f • '[ *yi*tr•>NX •*M*'f / " .•'••'.''•"/. - ':'.'':: -" " •• o:LU g Q OctCD i=" SOIL CLASS (USCS) CL CL SM ML T*/~\T*TVT/^ Ti~\ II A ABORING BM 44 ELEV. (MSL.) 491 DATE COMPLETED 5/21/96 EQUIPMENT E-120 MATERIAL DESCRIPTION Colluvium Stiff, moist, olive brown, fine Sandy CLAY DELMAR FORMATION Hard, damp, green, Silty CLAYSTONE; highly weathered to 7 feet with abundant calcium carbonate -Very fractured and blocky below 7 feet, crumbles with one blow of hammer -Prominent lens of calcium carbonate at 8 feet; 8 degree; S46W -Zone of heavy calcium carbonate replacement from 8 to 9 feet -Becomes less fractured and blocky at 9.5 feet Dense, damp, light grey, Silty fine SANDSTONE -Becomes orange, Sandy shell hash with low cohesion at 14.2 feet -5 inch thick green clay stone lens at 15.6 feet -One foot thick cemented concretionary bed at 16.1 feet, difficult drilling -Abrupt decrease in shell content at 19.8 feet -6 inch thick green siltstone lens at 21 feet; siltstone/sandstone is cut by several near vertical subparallel fractures in a one foot wide band, approx. trend N75W, 1/8" opening along fractures, no offset observed at siltstone/sandstone contact, fractures can be followed to 25 feet in depth Dense, damp, light green, fine Sandy SILTSTONE; occasional concretions -Becomes very stiff and thinly laminated at 28 feet -Slight to moderate seepage along fractures at 29 feet 0^" <ES^co j~" Hpi LU^CD 2 > H^CO) , L^CJQ . >£ Q ~ £*) 0)^H y=io Figure A-9 Log of Boring BM 44, page 1 of 2 RC09 SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED) ^ ... DISTURBED OR BAG SAMPLE E ... CHUNK SAMPLE I ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. PROJECT NO. 04787-12-09 DEPTH IN FEET - 32 - - 36 - - 40 - - 42 - - 44 - - 46 - - 48 - - 50 - - 52 - SAMPLE NO. JM44-3 1 JM44-4 LI T H O L O G Y \ GR O U N D W A T E R SOIL CLASS (USCS) ML CL CL BORING BM44 ELEV. (MSL.) 491 DATE COMPLETED 5/21/96 EQUIPMENT E-120 MATERIAL DESCRIPTION -Moderate seepage at 32 feet Hard damp, light to medium green, Silty CLAYSTONE; highly fractured and weak -Bedding Plane Shear at 34.3 feet (Near horizontal); 1/8" to 1" thick moist, dark green, remolded plastic bedding plane shear is enveloped in 4 inch thick highly sheared crumbly claystone with several additional discontinuous remolded clay seams -One inch wide open fracture in south side of boring at 35 feet; approx. trend north-south, 85 east, heavy water flow with minor caving, fracture can be followed to a depth of 40 feet -Bedding Plane Shear at 37.5 feet (Near horizontal); 1/2" thick moist, green, remolded plastic clay, well developed and continuous -Grades to Clayey SILTSTONE/ Silty CLAYSTONE at 38 feet -Difficult to log below 38 feet due to water and minor caving -Bedding Plane Shear at 44.2 feet (Near horizontal); 1" to 2" thick, moist, green, highly remolded plastic clay, very well developed and continuous around boring -Down hole logging terminated at 50 feet due to spoils in base of boring from caving BORING TERMINATED AT 53 FEET PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) - 2 - - >- §£ a MO I S T U R E CO N T E N T ( X ) Figure A-10 Log of Boring BM 44, page 2 of 2 RC09 CA**™ T- rnn,n^T oSAMPLE SYMBOLS ... SAMPLING UNSUCCESSFUL C . . . STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED) ... DISTURBED OR BAG SAMPLE kl . . . CHUNK SAMPLE f. . . . WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. APPENDIX fa pm r b m APPENDIX B - SLOPE STABILITY ANALYSIS FOR mm m RANCHO CARRILLO .. CARLSBAD, CALIFORNIA ** Project No. 04787-12-09 510 r— XH 490 Rancho Carillo Section A-A' 470 460 150 440 430 420 410 400 390 |— 40 Feet —I Melrose Drive STA 119+65 370 360 '250 30C Project No. 04554- 12-C June 20, 1996 350 Figure B-1 Rancho Carillo Section B-B' 590 580 570 560 550 540 ™ 520 510 500 490 Buttress Fill h/5 Feet ^ 470 200 Project No. 04354-12-C June 20, 1996 400 Figure B-2