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Home My WebLink AboutCT 99-09; RANCHO CARRILLO VILLAGE N; SUPPLEMENTAL GEOTECHNICAL INVESTIGATION AND SLOPE STABILITY ANALYSES; 1997-09-25SUPPLEMENTAL GEOTECHNICAL INVESTIGATION AND SLOPE STABILITY ANALYSES VILLAGE N RANCHO CARRILLO CARLSBAD, CALIFORNIA 314 75 ('2' OCT 1991. Lo RECEIVED \ le PREPARED FOR • • RANCHOCARRiLLO,INC. SAN DIEGO, CALIFORNIA SEPTEMBER 1997 GEOC.ON I N'C 0 B P 0 B A T B D I GEOTECHNICAL CONSULTANTS I Project No. 05845-12-01C '1 September 25, 1997 Cf I Rancho Carrillo Inc. ri V 10~ 12636 High Bluff Drive, Suite 300 5) San Diego, California 92130 I Attention: Mr. Dave Lother Subject: RANCHO CARRILLO CARLSBAD, CALIFORNIA I SUPPLEMENTAL GEOTECHNICAL INVESTIGATION AND SLOPE STABILITY ANALYSES, VILLAGE N I Gentlemen: In accordance with your authorization, we have performed a supplemental geotechnical investigation I for the proposed cut slope along the southern margin of Village N in the Rancho Carrillo subdivision. The intent of the study was to further evaluate the geologic conditions anticipated in the proposed slope area, and based on those conditions, provide design recommendations for slope I buttressing if necessary. In addition, the stability of the temporary slope backcut associated with buttressing was evaluated. I Based on the results of this supplemental study, it is our opinion that the proposed cut slope along the southern margin of Village N will require buttressing due to the presence of a weak bedrock shear zone that will "daylight" near the base of the slope subsequent to grading. The accompanying report presents the findings from our study and our conclusions and recommendations relative to the I slope buttressing as proposed. If you have any questions regarding this correspondence, or if we may be of further service, please I contact the undersigned at your convenience. Very truly yours, GE GEOCO AMR EVANS No so W CENWO i TORAT No. David B. Evans 31310 GE 5 • CEG 1860 DBE.TVL.dmc (6/del) Addressee (1/del) Southern California Soil and Testing Inc. Attention: Mr. Chris Christian 6960 Flanders Drive • San Diego, California 92121-2974 • Telephone (619) 558-6900 • Fax (619) 558-6159 I • I S. I / TABLE OF CONTENTS PURPOSE AND SCOPE...................................................................................................................... SUBSURFACE EXPLORATION ....................................................... ....................... ..........................2 SLOPE STABILITY. EVALUATION ....... ...........................................................................................3 I CONCLUSIONS AND RECOMMENDATIONS 6 LIMITATIONS AND UNIFORMITY OF CONDITIONS MAPS AND ILLUSTRATIONS Figure 1, Geology Map (11x17) I Figure 2, Geologic Cross 'Section . . I APPENDIX A . . FIELD INVESTIGATION . Figures A-i - A-3, Log of Exploratory Boring August 1997 (B8) I Figures A-4 A-6, Log of Exploratory Boring November 1991 (BM 1) Figure A-7 - A-8, Log of Exploratory Boring December 1991 (BP7) I APPENDIX B . . LABORATORY TESTING Table B-I, Summary of Laboratory Maximum Dry Density and Optimum Moisture ' 1 Content. Test Results '. Table B-IT, Summary of Direct Shear Test Results I APPENDIX SLOPE STABILITY ANALYSIS SLOPEIW VERSION 3 I Figures C-i Through C-6 . I I SUPPLEMENTAL GEOTECHNICAL INVESTIGATION AND SLOPE STABILITY ANALYSES, VILLAGE N 1. PURPOSE AND SCOPE I This report presents the findings from a supplemental geotechnical study performed along the southern margin of Village N within the Rancho Carrillo subdivision in Carlsbad, California. The I purpose of the field investigation was to further evaluate the geologic conditions in the vicinity of the proposed cut slope, and determine if slope buttressing is necessary based on the conditions encountered. I The geotechnical investigation performed in 1991 (Reference No. 3) encountered a 1/8-inch 1/4-inch I thick bedding plane shear in boring BM1 at an approximate elevation of 486 MSL. The boring was located approximately 300 to 500 feet north east of the proposed cut slope in Village N and focused on evaluating the geologic conditions and the need for buttressing in the vicinity of the proposed Melrose Avenue cut slopes. As part of the original study, a detailed log of the existing temporary cut slope was performed along the southern project boundary at Melrose Avenue Station 139+40 to 140+40 to evaluate the continuity of the shear zone encountered in boring BM 1. The logging encompassed an area where the projected bedding plane shear would daylight in the temporary slope I face. The bedding plane shear was not observed in the existing slope suggesting that it was discontinuous to the south. For this reason, buttressing in Village N was not proposed at that time. I The scope of this supplemental investigation included a review of previous geotechnical reports by Geocon Incorporated pertaining to Village N (see below), performing one exploratory boring in the I vicinity of the proposed cut slope to evaluate the continuity of the bedding plane shear encountered in boring BM1, and not observed during slope logging, and performing laboratory testing on a I bedding plane shear sample obtained during the study. Additionally, the stability of as-graded site conditions in the vicinity of the proposed cut slope based on the findings of this supplemental study I and previous investigations was evaluated. As part of the evaluation, buttress design and temporary backcut stability analyses was performed. The documents reviewed during this study include: I 1. Grading Plans, Rancho Carrillo, sheet 51 (scale 1 inch equal to 40 feet), and Grading Plans, Rancho Carrillo Melrose Drive, sheet 15, (scale 1 inch equals 40 feet) prepared by Rick I Engineering Company, approval date November 14, 1996. Preliminary Geotechnical Investigation for Rancho Carrillo Villages N, 0, Q, R, T, and U, I dated February 16, 1993. Geotechnical Investigation for Rancho Carrillo Project - Major Roads, Carlsbad, California, dated January 15, 1993. I Project No. 05845-12-0IC - - September 25, 1997 I I The supplemental field investigation was performed on August 11, 1997 in conjunction with a supplemental study conducted in Ranch Carrillo Villages Q and R. The field work consisted of drilling one large-diameter boring to a depth of 67 feet approximately 100 feet north of the proposed cut slope (see Geologic Map, Figure 1). The soil conditions and geologic structure were evaluated "down-hole" by an engineering geologist during the study. Details of the field investigation as well as a descriptive log of the boring (B8) are presented in Appendix A. The log of borings BP7 and BM from Reference Nos. 2 and 3 have been included for reference. A laboratory residual shear test was performed on a sample of the bedding plane shear material encountered during this study. The shear results, as well as soil strength properties from laboratory testing on samples-obtained during the investigation for the adjacent villages Q and R, and previous studies within the project were used to perform the slope stability analyses presented herein. Details of the laboratory tests and a summary of the test results are presented in Appendix B. I The Geology Map, Figure 1, is a composite base map derived from the two sheets listed in Reference No. 1. The map is presented at a scale of 1-inch equals 50 feet and depicts the boring locations from I . recent and previous studies (B8, BP7). Boring BM1 from Reference No. 3 is not shown but was excavated approximately 300 feet northeast of B8 along at the centerline of Melrose Avenue Station 136+50. The map also presents the configuration of selected portions of the proposed I development (sheet grade), site topography prior to grading, general geology and the location of the geologic cross section D-D' which was the basis for our slope stability analyses (Figure 2). The geologic cross section represents the estimated as-graded condition which will be present upon I the completion of interim sheet grading. Subsurface information from this study and previous phases of investigation was used to develop the cross section. It is anticipated that the ultimate grading in Village N will consist of cutting the southeastern portion of the village and filling the I north and western portions. Cuts and fills on the order of approximately 5 feet will likely be required to achieve the ultimate site configuration which should not affect the gross stability of the I buttressed slope provided that additional deeper bedding plane shears are not encountered. The conclusions and recommendations presented are based on an analysis of the data obtained from the exploratory field investigations, laboratory tests, slope stability, evaluation and our experience, with I similar soil and geologic conditions. 1 2. SUBSURFACE EXPLORATION I Boring No. 8 was excavated to a depth of 67 feet, approximately 100 feet north of the proposed cut slope on the southern boundary of Village N. The boring was intended to explore the zone between elevation 470 MSL and 510 MSL and identify possible bedrock shears that could be exposed in the Project No. 05845-12-01C - 2 - September 25, 1997 I . I I proposed cut slope to the south. It was also intended to characterize the geologic materials in the primary cut area with regard to soil strength and expansion potential for use in buttress construction and capping of the upper portions of finish grade in other areas of the-site. Boring No. 8 penetrated a well developed bedding plane shear consisting of a 1/2-inch to 1Y2-inch I thick soft moist remolded plastic clay at an elevation of 483 MSL. Several discontinuous secondary shears were also present below the plane. The main shear was dipping 4-degrees generally east but I is believed to be relatively horizontal with minor undulations over a broad area. A comparison of the elevation at which the bedding plane shears occur in B8 and BM1 (483 MSL and 486 MSL), and I the geologic materials surrounding the planes suggest that the they are the same continuous feature which occurs within the same general stratigraphic unit. I A temporary cut slope for recent excavations along the west side of Melrose Avenue (Station 137 area) was observed on September 18, 1997. The slope was approximately 35 feet high and generally I inclined at 1:1 (horizontal:vertical) or steeper. A well developed bedding plane shear was exposed at an approximate elevation of 483 MSL along the base of the temporary slope for a distance of at least I 100 feet to the north. The exposure confirmed the continuity of the bedding plane shear encountered in boring BM1 and boring B8. If this feature extends south and west, and remains continuous and generally horizontal, the bedding plane shear will daylight in the proposed cut slope along on the I project boundary. This condition was the basis for the stability evaluation presented herein. 3.. SLOPE STABILITY EVALUATION I .-Slope stability analyses were performed on the anticipated as-graded configuration along cross section D-D' (Figure 2) which transects the southern boundary of Village N (see Figure 1). The analyses considered the interim sheet grading geometry and assume that only relatively minor I modifications to this condition will result from the final grading. The results of the analyses are' presented on Figures C-i through C-4 which depict the most critical failure surface for each I .condition. As part of this study, stability analyses were also performed for the temporary backcut anticipated during buttress construction (Figures C-S and C-6). A discussion of our findings and recommendations are presented herein. I The stability analyses performed during this study assumed that the bedding plane shear encountered I during the investigations and grading is continuous, well developed and possesses an out of slope dip of 4 degrees. Although it is our interpretation that these shears are generally horizontal over a broad I area, the stability analyses assumed an out of slope dip component to consider a possible localized undulation within the shear similar to that measured in boring B8. It was also assumed that no I. .. Project No. 05845-12-0IC -3. . September 25, 1997 continuous bedding plane shears occur below an approximate elevation of 483 suggested by the information from borings B8 and BP7. The analyses utilized the computer software program SLOPE/W Version 3 (Spencers Method) to determine the factor of safety against deep-seated failure. The results of the analysis indicate that the proposed 2:1 cut slope with a continuous bedding plane shear outcropping near the toe of the slope possesses a factor of safety of less than 1.5. The same slope possessed a factor of safety in I excess of 1.9 with the construction of a buttress fill as recommended herein. The slope geometry, geologic structure, 'shear strength parameters and calculated factor of safety for each condition evaluated during the stability analyses are presented in Appendix C. The ,site geology, results of the subsurface investigations, laboratory testing, topography and I proposed finish grade surface were considered in the stability analyses. The cross section geometry of the subsurface conditions was developed by extrapolating the information obtained in the I exploratory excavations. The computer generated cross-sections presented in Appendix C represent simplified configurations which were used in the analyses. The cross-section presented on Figure 2 is the original geologic section from which the computer generated section was derived. Drained shear tests were performed on relatively undisturbed samples of the prevailing lithologic I units encountered during the recent study in the adjacent village. A residual shear test was also performed on a sample of the bedding plane shear encountered in Village N (boring 138) to evaluate I ' the strength parameters representative of well developed bedding-plane shears. In addition, the shear strength values of prior laboratory testing on this project were considered in the stability evaluation. The results of the shear tests are presented in Table B-IT of Appendix B. The strength parameters from remolded samples of formational soils used during buttressing in the I adjacent village are presented in Appendix B. The strength values represent typical "select" material derived from on-site cuts within the Delmar Formation. The Village N evaluation assumed that I "select" material would not be available for use in buttress construction. The following table presents the soil strength parameters that were utilized in the analyses. 1'• E I I Project No. 05845-12-01C -4- : September 25, 1997 I' TABLE 3. SOIL STRENGTH PARAMETERS Angle of Cohesion Soil Condition Internal Friction 4) (degrees) c (psi) Delmar Formation 32 500 Compacted Fill 20 .350 Bedding Plane Shear 10 50 Figures c-i through C-4 depict the lowest factor of safety determined for the proposed buttressed slope assuming two different modes of slope instability and assuming that the bedding plane shear is either horizontal or dipping out of slope at 4 degrees. The findings from our borings and observations during grading indicate that the bedding plane shear is near horizontal over large distances but localized areas may dip up to 4 degrees. The buttress used in the analyses is based on a 1:1 backcut commencing at the top of the slope and extending downward to 5 feet below the bedding plane shear. The results of the analyses yielded a minimum factor of safety of 1.97 with respect to deep-seated failure. Figures C-S and C-6 represent the lowest factor of safety determined for slope instability along the bedding plane shear (horizontal and dipping) during the temporary backcut excavation for the buttress. These analyses yield a minimum factor of safety of 1.27. In our opinion this factor of safety is acceptable considering the conservation assumptions made and our experience with other temporary steep excavations made on the property in similar geologic conditions. Project No. 05845-12-01C -5- September 25, 1997 I I 4. CONCLUSIONS AND RECOMMENDATIONS I 4.1. The results of this study indicate that the proposed cut slope along the southern margin, of Village N will require buttressing due to the presence of a bedding plane shear zone within the Delmar Formation at a general elevation of 485 MSL. The shear zone was I ' encountered in several nearby exploratory excavations, and during recent grading operations and is assumed to be continuous and horizontal. If this is the' case, the shear. ' will daylight near the base of the cut slope. The proposed slope stabilization measures will result in a factor of safety of at least 1.5 with respect to deep seated instability. U 4.2. The proposed buttress should be constructed in accordance with the typical buttress detail presented in the project geotechnical reports. The estimated horizontal limits of the I ' proposed buttress are presented on Figure 1. The temporary backcut should originate at the proposed top of slope and extend northward at an inclination of 1:1. The heel drain I ' system should grade at a minimum of 1 percent westward and outlet in the proposed brow ditch at the western end of the slope. Field conditions may dictate minor variations in the anticipated drainage and buttress geometty. The buttress fill soil should posses minimum I soil strength parameters of 0 = 20 and C = 350. 1 4.3. Construction of the buttress will require a segmented procedure. The temporary 1:1 Ok.-., backcut should be advanced to an elevation of approximately 5 feet the bedding plane shear zone (elevation 490 MSL). Segments should then be removed in 100-foot increments with adjacent segments completely backfilled to an elevation of 490 MSL prior to beginning the next increment. Excavation segments should not remain open overnight I without at least partial backfill to a minimum elevation determined by the Geocon field representative. I ' ' i r 5—, ,k (ôc)' I ' I U 'LN g2 I ' I Project No. 05845-12-01 C - 6 - ' September 25, 1997 I ,' LIMITATIONS AND UNIFORMITY OF CONDITIONS The recommendations of this report pertain only to the site investigated and are based upon the assumption that the soil conditions do not deviate from those disclosed in the investiga- tion. 'If any variations or undesirable conditions, are encountered during construction, or if the proposed construction will differ from that anticipated herein, Geocon Incorporated should be notified, so that supplemental recommendations can be given. The evaluation or identification of the potential presence of hazardous or corrosive materials was not part of the scope of services provided by Geocon Incorporated. This report is issued with the understanding that it is the responsibility of the owner, or of his representative, to ensure that the information and recommendations contained herein are brought.to the attention of the architect and engineer for the project and incorporated into the plans, and the necessary steps are taken to see that the contractor and subcontractors carry out such recommendations in the field. The findings of this report are valid as of the present date. However, changes in the conditions of a property can occur with the passage of time, whether they be due to natural processes or the works of man on this or adjacent properties.. In addition, changes in applicable or appropriate standards may occur, whether they result from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by changes outside, our control. Therefore, this report is subject to review and should not be relied upon after a period of three years. Project No. 05845-12-01 C September 25, 1997 I I RANCHOCARRILLOJ VILLAGE N 440 :1! .... CARLSBAD, CALIFORNIA i -D /i A .4 _ 7 ;.J\.\\'rLL± B-8(1997) / / / SCALE 1 =50 540 LIMIT 520 3f) _7-17 - - S PROJECT Ol'ND4R 56'. _____ 1 Po .i&cr T : . , .I•_____ •..•.. •..4 •••i . \.\.\ \ - GEOCON LEGEND •- - - - . - . .. .•• 1 .;. LOCATION OF EXPLORATORY BORING PERFORMED IN 1997 _• BP7®APPROX. LOCATION OF EXPLORATORY BORING PREFORMED IN 1991 • \ .•... • • 1 ........ APPROX. LOCATION OF GEOLOGIC CROSS SECTION GEOLOGY MAP 500 S GEOCON ww~ INCORPORATED 0 1 FIGURE I J 6960 RANDEPS DRIVE - SAN DIEGO, CALFORRA 9'2121-297A I :. .. SUPPLEMENTAL GEOTECHNICAL INVESTIGATION AND STABILITY ANALYSIS DATE 09-25-1997 - - H I 440' -' 520' - z 0 I- < 500'- > LIJ -J w 480' - 460'- 560'- 540'- o 0' 20' 40' 60' 80' 100' 120' 140' 160' 180' :8 SM ...EXISTINGGRADE CL Td SM CL Td PROPOSED BUTTRESS SM - ML/CL BEDDING PLANE SHEAR ASSUMED CONTINUOUS AND HORIZONTAL 480' RFFLJSAL PROPOSED SHEET GRADE - -460' LEGEND Td. .... ...DELMAR FORMATION CROSS-SECTION D-D' 1' SCALE: 1=20' (HORIZ.=VERT.) GE000N 4 INCORPORATED GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE . SAN DIEGO, CALIFORNIA 92121-2974 PHONE 619 558-6900 . FAX 619 558-6159 PROJECT NO. 05845-12-01 SUPPLEMENTAL GEOTECHNICAL INVESTIGATION AND STABILITY ANALYSIS FIGURE 2 BACKCUT FE RANCHO CARRILLO VILLAGE N CARLSBAD, CALIFORNIA D' 200' 220' 240' 260' 280' I I -560' -540' PROJECTED BUILDING -520' z 0 APPENDIX A FIELD INVESTIGATION The field investigation was performed on August 11, 1997, in conjunction with the Village Q/R study and consisted of a visual site reconnaissance of the conditions exposed during grading and the excavation of one large-diameter boring. The, approximate locations of the exploratory boring that was performed during this study and a boring from our.previous investigation is shown on Figure 1. The large-diameter boring was advanced to a depth of 67 feet below existing grade using an Easy Bore 120 truck-mounted drill rig equipped with a 30-inch-diameter bucket auger. A.chunk.sample of the bedding plane shear'material encountered at a depth of 62 feet was obtained, sealed in a plastic bag, and transported to our laboratory for residual shear strength testing. The soils encountered in the boring were visually examined, classified, and logged. Logs of the boring from this study and prior investigations are presented on Figures A-I through A-8. The logs depict the soil and geologic-conditions encountered and the depth at which the sample was obtained. Project No. 05845-12-01C September 25, 1997 Figure A-i Log of Boring B 8, page 1 of 3 RCVN S SAMPLE SYMBOLS El SAMPLING UNSUCCESSFUL 11 ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED' DISTURBED OR BAG SAMPLE 10 ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE j I PROJECT NO. 05845-12-01 )- W Tb 0 DU1'(JI'iflO z DEPTH SAMPLE SOIL \J IN FEET CLASS ELEV. (MSL.) 545 DATE COMPLETED 8/11/97 tw 0 (USCS) CD EQUIPMENT '- 0 Ci MATERIAL DESCRIPTION 0 7/ - CL TOPSOIL - Loose, dry, light brown, fine Sandy CLAY DELMAR FORMATION - - :. Dense, damp, orange-brown, Silty, fine to medium - - 4 - ::::: SANDSTONE, massive and friable - - 6 - SM -Highly cemented concretionary bed with abundant - - - shells from 9 to 12 feet, core barrell required to - excavate 8 - 10 - 12 - - - Orange friable fossiliferous SANDSTONE lense SM - 14 - :-::- ---------------------------------------- - - - 16 - __ Hard, damp, green and orange, Silty CLAYSTONE; / concretionary and fossiliferous zones -18 - CL - -20 - 22 - ---------------------------------------- .t't. - Dense, damp, orange-brown, Silty fine SANDSTONE/fine Sandy SILTSTONE - 24 M/ML - 26 - - ::[: - 28 -Becomes sandstone 29 feet primarily at - 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. I i Figure A-2 Log of Boring B 8, page 2 of 3 SAMPLE SYMBOLS 0 ... SAMPLING UNSUCCESSFUL El ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED) I DISTURBED OR BAG SAMPLE iJ ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE I PROJECT NO. 05845-12-01 BORING B 8 DEPTH 0 Cc SOIL . " IN SAMPLE NO. CLASS ELEV. (MSL.) 545 DATE COMPLETED. 8/11/97 i4n wj FEET (USCS) WU)O . C0 CnW H EQUIPMENT MATERIAL DESCRIPTION 30 - 32 - M/ML -Becomes fine to coarse SANDSTONE at 32 feet - - 34 - -One-foot-thick highly cemented zone at 33.5 feet 36 - :•.•:t _______ - Hard, damp, green, Silty CLAYSTONE; fractured and blocky 38 - 40 CL 42 - - 44 - - -Some Sandy SILTSTONE zones below 45 feet 46 - - 48 - - 50 - - -One-foot-thick concretionary bed at 51 feet - 52 - - - Dense, moist, orange, fossiliferous SANDSTONE; SM abundant concretionary zones, difficult drilling - 54 - - 56 - I Very stiff to hard, damp to moist, light green, Clayey SILTSTONE/Silty CLAYSTONE; orange oxide - - ML/CL . staining 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. I PROJECT NO. 05845-12-01 BORINGBS DEPTH SAMPLE ' o SOIL o LL. Ir IN FEET NO • Z CLASS ELEV. (MSL.) 545 DATE COMPLETED 8/11/97 cn w • '- . CD (USCS) EQUIPMENT z _j :i 'WHO 0 -' H a. ce 0 Ci MATERIAL DESCRIPTION -- 60 -Becomes very stiff and thinly laminated with moist - - clay planes along laminations at 59 feet - -62 - 138-1.- / BEDDING PLANE SHEAR AT 62 FEET (4,N88E); - - 1/2-inch to 1-1/2-inch thick, soft, moist, light - 4 grayish green, remolded plastic clay, very well - 64 - I = 4L/CL developed and continuous; several secondary - - - discontinuous shears below main plane -, - • -Grades to cemented Sandy SILTSTONE at 64 feet * - 66 - -Slight seepage at 64 feet - • -Core barrel for 1/2 hour at 67 feet REFUSAL AT 67 FEET - • Figure A-3 Log of Boring B 8, page 3, of 3 • SAMPLE SYMBOLS ... SAMPLING UNSUCCESSFUL II... STANDARD PENETRATION TEST I ... DRIVE SAMPLE (UNDISTURBED) DISTURBED OR BAG SAMPLE .. CHUNK SAMPLE • ... WATER TABLE OR SEEPAGE I 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. 04787-12-01 DEPTH FEET IN NO. SAMPLE z SOIL CLASS (USCS) BORING BM 1 ELEV. (MSL) 535 DATE COMPLETED 11/12/91 EQUIPMENT E-100 BUCKET RIG 01 _\ Z >..o. 9 Uj X I- o 8 MATERIAL DESCRIPTION 30 - - - BMl- ::TTT SM Dense, damp, light brown to light grey, Silty, fine to medium SANDSTONE 15 139.4 1.9 - - - - - (Continued) . -Highly cemented concretion in north rr- - - - _____ 1/2 of boring from 31 to 33 feet -Interbedded olive-green claystone and - 34 CL-SC orange-brown fossiliferous clayey sandstone; subhorizontal bedding, orange- - - 36 BMI-9 - yellow oxide stains at 33 feet - 6 124.6 11.2 -_ -- - - 38 - - - 40 - - IMI 1( MJ11 CH -Series of wet yellow-brown-dark red waxy clay seams, subhorizontal to N72E,33NW from 36 to 38 feet I - - - - i5ené 1ri moist, faje-6zow-- Silty, fine to coarse SANDSTONE: fossiliferous - : - SM 6 - 122.0 10.7 -Slight seepage from 38 to 41 feet - 42 - - 44 - -Highly cemented, fossiliferous concretion - - - )IVJI-14 - from 44 to 45 feet damp to moist, light green, Silty - . - 46 -Hard, - CLAYSTONE - CL - -Shear plane N35W, 4NE at 47 feet -48- - -3 to 8 inch highly cemented sandstone, - - subhorizontal at 48.5 feet - - 50 - IMI-L : -Bedding Plane Fault at 493 feet; 1/8 to 1/4 inch green to orange, wet clay N35W,4NE - 8 110.2 19.1 - Ml-1 E -. -52- -- - - 54 - -Highly cemented sandstone, subhorizontal - from 53 to 55 feet Ml-1 - - - - 20 121.7 14.4 - 56 - - - Ml-1 CL -Becomes very hard, blue-green claystone at55feet - - - 58 - -Highly cemented, fossiliferous concretionary bed from 58 to 60 feet - - Log of Boring BM 1, page 2 of 3 CROR I SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL - 11.... STANDARD. PENETRATION TEST U. DRIVE SAMPLE (UNDISTURBED) ... DISTURBED OR BAG SAMPLE ..... CHUNK SAMPLE f... WATER TABLE 0R SEEPAGE I THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY Al 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 TINES. I Figure A- 4 PROJECT NO. 04787-12-01 >-LLI BORING BM 1 DEPTH SAMPLE 0 '- SOIL <E xZ zU. Uj LL IN NO. z CLASS ELEV. (MSL) 535 DATE COMPLETED 11/12/91 m 24 U) I-3 Ui • Q9 Z ui FEET (USCS) _j >.Q. 0 - EQUIPMENT E-100 BUCKET RIG a. Z - MATERIAL DESCRIPTION 0 CL TOPSOIL Stiff, dry to damp, dark brown, Sandy 2 - BM1-1 SM CLAY; 1/2 to 1 inch roots, desiccation 3 107.8 7.1 - cracks - 4 - DELMAR FORMATION Dense, damp, light brown to light grey, BMI-2 - Silty fine to medium SANDSTONE: 9 108.0 4.7 6 - : - 1/4 to 2 inch discordant veins BM13 of caliche, thin oxidized lenses -Cohesionless orange, fine to coarse sand SP - 8 - with shell fragments from 7 to 8 feet - . - - -Highly cemented concretionary bed - from 8 to 9.5 feet :I:H:I 7 120 0 9.4 - 10 - BM1-4 SM -Caliche filled fracture N26E, 575E - at 10.5 feet -12- -Sandstone/concretionary bed at 12 feet - - - -1/8 to 1/2 inch open fracture : - - IA - .. -: N20E, 85NW from 12.5 to 22 feet :.: M -CL-M - BM1-5 :. -: Very dense, damp li , ght green, SILTSTONE/ , 1174 11.2 CLAYSTONE interbedded with very dense, - 16 damp, orange/light green, Silty SANDSTONE - - : -Fractures: N-S, 90; N45E, 85NW - - at 16 feet - 18 - - 20 - BMl6 F. -1/2 to 2 inch open fracture - 6 118.6 11.3 - - :--: N73E, 855E at 20 feet - - 22 - -1/4 to 1/2 inch open fracture N28E, 86NW at 23 to 24 feet - 24 - _ - ____ - Hard damp, light to dark green, BMl-7 L-CH CLAYSTONE; orange oxide staining, 10 117.6 15.6 26 - 1/4 to 1 inch, wet, orange/green, clay - seam, N3OW, 6NE at 25.5 fl : - - -- eie hfrbWfl1ciflg1t?ay 28 - IF Silty, fine to medium SANDSTONE - SM F -Fracture N46E, 83NW from 28 to 30 feet - Log of boring bM. 1, page 1. of a 1 SAMPLE SYMBOLS 0.._ SAMPLING _UNSUCCESSFUL IJ ... STANDARDPENETRATION_TEST I.. - ..DRIVESAMPLE(UNDISTURBED) DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE Y ... WATER TABLE OR SEEPAGE I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING. OR TRENCH LOCATIOPI AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO. BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.. I.- Figure A- 5 t PROJECT NO. 04787-12-01 LLI 1 • DEPTH SOIL FE IN ET SA NO. z MPLE CLASS BORING BM 1 ELEV. (MSL) 535 DATE COMPLETED 11/12/91 EQUIPMENT E-100 BUCKET RIG a. M 8 MATERIAL DESCRIPTION 60 - 62 - 64 - 66- 68- • 70- 72- - I .74. M171 I MI-1 CL • Hard, blue-green claystone (Continued) -Becomes dark green to black claystone at 64 feet •. -Highly cemented, fossiliferous at 69 feet - 30 - - - - - 120.2 117.7 14.4 16.3 - BORING TERMINATED AT 74 FEET PRACTICAL REFUSAL :. i Figure. A.- 6 Log of Boring BM 1, page 3 of 3 CROR SAMPLE SYMBOLS 0 . SAMPLING UNSUCCESSFUL 13. .... STANDARD PENETRATION TEST I. .,.. DRIVE SAMPLE (UNDISTURBED) DISTURBED OR BAG; SAMPLE .....CHUNK SAMPLE . Y..... WATER TABLE OR SEEPAGE. I 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 TOM REPRESENTATIVE OF SUBSURFACE CONDITIONS. AT OTHER LOCATIONS AND TIMES I tROJECT NO. 04354-12-03 DEPTH SAMPLE - H SOIL CLASS (USCS) FEET W BORING BP 7 ELEY. (MSL) 490 DATE COMPLETED 12/23/91 EQUIPMENT E-100 BUCKET RIG <r <r In z0 0 ow z L. >-a.o uJ 0 MATERIAL DESCRIPTION CL TOPSOIL Stiff, moist, medium to dark brown, 2 BP7 Sandy CLAY: 1/4 to 1/2 inch rootlets - 2 iou 15.3 I -I SM - FORMATIONAL CREEP - Medium dense, dry to damp, light to orange - brown, Silty, fine to medium SANDSTONE,- - 6 - BP7 -2 - highly weathered with mottled appearance -Sharp contact at 6.5 feet N2E, 9SE -2 to 4 inch soft laminated clayey - 7 - 112.4 6.2 :• - - '\ fine sandstone at contact - - I - 10 BP7 -3 : SM-SC 8 - 6/8" 112.0 15.5 DELMAR FORMATION Medium dense to dense, damp, light green, Silty, Clayey, fine SANDSTONE: abundant I caliche and disseminated orange oxide SM _ Dense, damp, damp, orange-brown, Silty, fine_ SANDSTONE: highly fossiliferous 0IBI_II _ SM 12 111 -Cemented concretion at 10 feet - 14 - I -18- I - 16 :L-cF BP7 BP7 -6 inch layer of moist green/orange interbedded siltstone/claystone at 11.3 feet -Cemented concretion at 12 feet 1 , to olive green CLAYSTONE; thinly bedded I with oxide along bedding -Several soft, very moist, discontinuous clay seams along bedding, approx. attitude _____ SM ______ - 6 113.5 13.8 SM - SC-CL I - 20 BP7 6 N75E, 4NW from 14 to 14.6 feet Dense, rn orange-brown, Sty, fine SANDSTONE - 6 - 111.5 16.2 I - 22 L_.... _•u Stifffyvyit to wet, : - - . 24 .• SMSC yditnifgit -- 1 medium to olive green, fine Sandy CLAY- STONE• interbedded orange fossiliferous sandstone and soft, moist to very moist clay I - 26 BP7 -7 - I - - - - d1ii iii d deh rid'him- ------- , light green, Silty, Clayey, fine I SANDSTONE: massive, oxide staining -3 - 28 CL I I. Stiff, moist, light gray to light green, fine Sandy CLAYSTONE - - -Zone of medium stiff, moist,, light green,. - I claystone from 25.5 to27 feet. thinly p Figure A— 7 Log of Boring- BP 7'. page 1 of 2 CROR SAMPLE SYMBOLS 0 .._ SAMPLING UNSUCCESSFUL II ... STANDARD PENETRATION TEST I.... DRIVE SAMPLE (UNDISTURBED) DISTURBED OR &AG SAMPLE .. CHUNK SAMPLE Y... WATER TABLE OR SEEPAGE I GTE: 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 BL REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.. j IPROJECT NO. 04354-12-03 BORING BP 7' DEPTH SOIL U. IN NO. SAMPLE a z a z CLASS ELEV. (MSL) 490 DATE COMPLETED 12/23/91 U) '- LU • Z ul FEET (USCS) ui U) >. a EQUIPMENT E-100 BUCKET RIG MATERIAL DESCRIPTION 30 -. - Sc bedded 77= 114.2 1.9 U . . -8 I -Cemented concretion at 28 feet I - BP7 32 -9 ' Dense, damp, light green, Clayey, fine - - - SANDSTONE I' :.•: SM-SC -Gradational contact with cemented - 34 concretion at contact - De se, damp, light grey to figh `giein - - - 7 I .BP7 36 • -10 - - Silty, Clayey, fine SANDSTONE - 138 : I . 40BP7 :.: - 5 A1O.3 17.6 1 TRENCH TERMINATED AT 41 FEET I I I I I I-'.. S -- 9gure A—B Log o Boring BR 7 page. 2 of 2 CROR SAMPLE SYMBOLS SAMPLINa UNSUCCESSFUL. I! ... STANDARD: PENETRATION TEST I. ... DRIVE SAMPLE (UNDISTURBED) ________________ •.. DISTURBED. OR BAG SAMPLE - CHUNK SAMPLE ... WATER TABLE. OR SEEPAGE I THE LOG OF SUBSURFACE CONDITIONS- SHOWN HEREON APPLIES ONLY AT THE SPECIFIC- BORINe OR TRENCH LOCATION AND Ar THE DATE INDICATED.. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS- AND TIMES.. APPENDIX I' I I i I I l I I r I I APPENDIX B LABORATORY TESTING I Laboratory tests were performed in general accordance with the test methods of the American I Society for Testing and Materials (ASTM) or other suggested procedures. Selected, relatively undisturbed drive samples obtained, from the adjacent Village Q/R study were tested for their in- place dry density, moisture content, and shear strength characteristics. The maximum dry density and optimum moisture content of selected bulk samples of the compacted fill derived from typical cuts within the Delmar Formation were determined in accordance with ASTM Test Procedure D 1557-91. Portions of the bulk samples were then remolded to selected densities and subjected to drained direct shear testing. The results of our laboratory tests are presented in tabular from hereinafter. The residual shear samples identified as BPI 1-7 and BP 19-9 were tested as part of earlier studies performed for the Rancho Carrillo project and are presented because they represent residual shear strength parameters of bedding plane shears. The in-place dry density and moisture characteristics are presented on the logs of the exploratory borings. TABLE B-I SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM D 1557-91 Sample Description Maximum Dry Optimum Moisture No. Density (pci) 'Content (% dry wt.) 33 Yellow-brown, Silty/Clayey fine to medium SAND 115.2 13.4 40 Light brown, Silty/Clayey fine to medium SAND 114.2 15.6 47 Yellow-brown, fine Sandy SILT with little clay 113.6 15.7 I I Project No. 05845-12-01C - B-i - September 25, 1997 I I I TABLE B-Il SUMMARY OF DIRECT SHEAR TEST RESULTS Sample No. Dry Density (pci) Moisture Content (%) Unit Cohesion (psi) Angle of Shear Resistance (degrees) 33* 103.7 13.5 525 3.1 40* . 102.9 15.4 650 - 32 47* 102.1 15.8 830 27 B4-3 92.3 . 30.5 745 9 109.1 19.3 185 45 134-9 , - 108:8 20.0 850 34 87.4 36.1 . 50 10 BP117*** 87.0 34.1 . 10 14 BP199*** 93.4 33.0 85 9 *Soil sample remolded to approximately 90 percent of maximum dry density at near optimum moisture content. Samples obtained from Village Q. **Sample cemented ***Residual Shear j Project No. 05845-12-0IC - B-2 - September 25, 1997 APPENDIX C SLOPE STABILITY ANALYSIS. SLOPEIW VERSION 3 for RANCHOCARRILLO.. CARLSBAD, CALIFORNIA PROJECT NO. 05845-12-0IC (I I . I ' 1• I I 1 I I I I I 1. - - - mm - M-,- - - - - - - - - - - - Project No. 05845-12-01C RANCHO CARRILLO VILLAGE N CROSS SECTION D - Df Buttress with 1:1 Backcut Horizontal Bedding Plane Shear 3.170 550 r Property Line 550 Soil Type Unit Weight (pcf) %(deg) Cohesion (psi) Qcf 130 20 350 B.P.S. 130 10 50 Td 130 32 500 Figure C-i 450 400 LL 0 500 0 50 100 150 200 Distance (ft) - - - - - - - - - - - - - - - - - - - Project No. 05845-12-01C RANCHO CARRILLO VILLAGE N CROSS SECTION D - Df Buttress with 1:1 Backcut Horizontal Bedding Plane Shear .• •'• 550 File: CarrDlbl.slp Soil Type Unit Weight (pci) %(deg) Cohesion (psi) Qef 130 20 350 B.P.S. 130 10 50 Td 130 32 500 Figure C-2 - - - - —. - - - - - - - - - - - - - - Project No. 05845-12-0IC RANCHO CARRILLO VILLAGE N CROSS SECTION D - Buttress with 1:1 Backcut Bedding Plane Shear Inclined 4 deg. Out of Slope 2.561 550 550 SOC 40C 0 50 100 150 200 Distance (ft) Soil Type Unit Weight (pci) 0 (deg) Cohesion (psi) Qcf 130 20 350 B.P.S. 130 10 50 Td 130 32 500 500 450 400 250 300 350 File: CarrDla.slp Figure C-3 L) 450 400 EL 0 500 C 50 100 150 200 Distance (ft) - - - - - - - - - - - - - - - - - mm Project No. 05845-12-01C RANCHO CARRILLO VILLAGE N CROSS SECTION D - Buttress with 1:1 Backcut Bedding Plane Shear Inclined 4 deg. Out of Slope .' .:.. -S 550 File: CarrDlal.slp Soil Type Unit Weight (pci) Ø(deg) Cohesion (psi) Qcf 130 20 350 B.P.S. 130 10 50 Td 130 32 500 Figure C-4 - - - - - - - MM - - - - MM NO - - - Project No. 05845-12-OIC RANCHO CARRILLO VILLAGE N CROSS SECTION D - D' Temporary 1:1 Backcut Horizontal Bedding Plane Shear 1.288 550 550 400 0 500 450 400 250 300 350 File: CarrDld.slp 50 100 . 150 200 Distance (ft) Soil Type Unit Weight (pcI) 0 (deg) Cohesion (psi) Td 130 32 500 B.P.S. 130 10 50 SOC r. 0 Figure C-5 - - - - - - - - - - - - - - - - - - - Project No. 05845-12-01C RANCHO CARRILLO VILLAGE N CROSS SECTION D - Temporary 1:1 Backcut Bedding Plane Shear Inclined 4 deg. Out of Slope 1.267 S 550 50( 40C 0 50 100 150 200 Distance (ft) Soil Type Unit Weight (pcf) Ø(deg) Cohesion (psi) Td 130 32 500 B.P.S. 130 10 50 550 500 450 400 250 300 350 File: CarrDlc.slp Figure C-6