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HomeMy WebLinkAboutCT 00-20; Fox Miller Property; Tentative Map (CT) (5)dfne 14 December 2001 Project No. 0-252-101400 Mr. Dean Miller c/o Flour Corporation 1 Enterprise Drive Aliso Viejo, CA 92656 RECEIVED DEC 1 9 2001 CITY OF CARLSBAD PLANNING DEPT. RE: Geotechnical Response to City of Carlsbad/Peer Review Comments Fox-Miller Property, CT 00-20, GPA 00-05 EI Camino Real, Carlsbad, CA Ref: AGRA, 2000, Geotechnical Investigation Update, Fox-Miller Property, Adjacent and Southerly of E! Camino Real, Faraday Avenue, Carlsbad, California, Project No. 0-252- 101400, dated 6 July 2000 AMEC, 2001, Second Response to City of Carlsbad Review Comments, Fox-Miller Property, CT 00-20, GPA 00-05, El Camino Real, Carlsbad, CA, Project No. 0-252- 101400, dated April 18, 2001 Buccola Engineering, Inc., 2001, Tentative Map for Fox-Miller Property, Carlsbad, California, 7 Sheets, dated 7 August 2001 Leighton and Associates, 2001, Peer Review of Geotechnical Recommendations forthe 1.5 to 1 (Horizontal to Vertical) Slope, Fox-Miller Property, Carlsbad Tract No. 00-20, Carlsbad, CA, Project No. 040581-001, dated 30 November 2001 Dear Mr. Miller; In accordance with the request of the Ladwig Design Group, we have prepared this letter in response to the Peer Review comment presented in the Leighton and Associates letter (referenced above) for the Fox-Miller Property. Based on the geotechnical review comment, we provide the following response: In accordance with the recommendation of the Leighton letter, we have performed an analysis of the eight currently proposed 4-foot vertical viewing "popouts" at the toe of the 1.5:1 slope along El Camino Real. The popouts are approximately 20 feet long. We have performed a slope stability analysis using the Janbu Circular Method and Block Method. Our assumed parameters are as follows: Assumed Parameters: (j) = Apparent soil friction angle c = Apparent soil cohesion = 27 degrees = 300 pounds per cubic foot AMEC Earth & Environmental, Inc. 5510 Morehouse Drive San Diego, CA 92121 Tel 1 (858) 458-9044 Fax 1 (858) 458-0943 www.amec.com RECEIVED DEC 1 B 2000 .ADwiG dmm m lO^ Mr. Dean IVliiler Fox-Miller Property Project No. 0-252-101400 14 December 2001 dfne The results of the stability analysis indicates a factor of safety greater than 3.0 for both cases (circular and block) modeled. As stated in our report (dated 6 July 2000) and our letter (dated 18 April 2001), even though the calculated safety factor is greater than 1.5, the slope, as well as the viewing "popouts", may be susceptible to shallow surficial instability which may cause eroded soil to accumulate at the base of the slope and "popouts" and necessitate frequent maintenance. Based on conversations with a representative ofthe Ladwig Design Group, Inc., we understand that an Owners Association will be required for the project. One function of this association will be to perform routine slope maintenance as well as other maintenance issues. The existence of this association will relieve the City of Carlsbad from the performance of the anticipated routine maintenance of the slopes on the project. In addition, the "popouts" are set a good distance away from the street and thus, accumulations of slough and soil at the base of the slope and viewing areas are not anticipated to negatively impact the existing roadway. If you have any questions regarding this letter, please do not hesitate to contact this office. We appreciate the opportunity to be of service. Respectfully submitted, AMEC Earth & Environmental, Inc. Joseph G{ Franzone, Gh2189 ising Engineer Attachments: Slope Stability Analysis Distribution: (2) Addressee (1) Ladwig Design Group, Inc. Attention: Mr. Bob Ladwig Q:\Shared\Projects\2000\0-252-101400 Fox-Miller\0-252-101400 Geot Response to City Review.doc Page 2 XSTABL File: FOXBL 12-14-** 14 : 12 ****************************************** * XSTABL * * * * Slope Stability Analysis * * using the * * Method of Slices * * * * Copyright (C) 1992 A 95 * * Interactive Software Designs, Inc. * * Moscow, ID 83843, U.S.A. * * * * All Rights Reserved * * * * Ver. 5.103 95 A 1387 * ****************************************** Problem Description : FOX MILLER SITE VIEW POP-OUTS BLOCK SEGMENT BOUNDARY COORDINATES 3 SURFACE boundary segments Segment No. 1 2 3 x-left (ft) . 0 20 . 0 20.1 y-left (ft) 20 . 0 20 . 0 24 . 0 x-right (ft) 20 . 0 20 . 1 50 . 0 y-right (ft) 20 . 0 24 . 0 44 . 0 Soil Unit Below Segment 1 1 1 ISOTROPIC Soil Parameters 1 Soil unit(s) specified Soil Unit Weight Cohesion Friction Pore Pressure Water Unit Moist Sat. Intercept Angle Parameter Constant Surface No. (pcf) (pcf) (psf) (deg) Ru (psf) No. 125.0 130 . 0 300.0 27 . 00 . 000 . 0 1 Water surface(s) have been specified Unit weight of water = 62.40 (pcf) Water Surface No. 1 specified by 2 coordinate points ********************************** PHREATIC SURFACE, ********************************** Point x-water y-water No. (ft) (ft) 1 .00 5.00 2 50.00 10.00 A critical failure surface searching method, using a random technique for generating sliding BLOCK surfaces, has been specified. The active and passive portions of the sliding surfaces are generated according to the Rankine theory. 50 trial surfaces will be generated and analyzed. 1 boxes specified for generation of central block base Length of line segments for active and passive portions of sliding block is 1.0 ft Box x-left y-left x-right y-right Width no. (ft) (ft) (ft) (ft) (ft) 1 20.0 19.4 21.5 24 .0 1.0 The trial failure surface in question is defined by the following 8 coordinate points oint X-surf y-surf No. (ft) (ft) 1 20.08 23.30 2 20.35 23 . 13 3 21.20 22 . 61 4 21. 73 23 .46 5 22 .25 24 .31 6 22 . 77 25 . 17 7 23 .29 26 . 02 8 23 .42 26.22 The trial failure surface in question is defined by the following 8 coordinate points Point x-surf y-surf No. (ft) (ft) 1 20.05 22.18 2 20.64 21.82 3 21.17 22.67 4 21.69 23.52 5 22.21 24.38 6 22.73 25.23 7 23.26 26.08 8 23.29 26.13 Factors of safety have been calculated by the : ***** SIMPLIFIED JANBU METHOD ***** The 10 most critical of all the failure surfaces examined are displayed below - the most critical first Failure surface No. 1 specified by 11 coordinate points Point x-surf y-surf No. (ft) (ft) 1 19.49 20.00 2 20.10 19.62 3 20.63 20.47 4 21.15 21.33 5 21.67 22.18 6 22.19 23.03 7 22 . 72 23.88 8 23.24 24.74 9 23.76 25.59 10 24.28 26.44 11 24.65 27.05 ** Corrected JANBU FOS = 3.129 ** (Fo factor = 1.037) Failure surface No. 2 specified by 13 coordinate points Point x-surf y-surf No. (ft) (ft) 1 18.33 20.00 2 19.17 19.49 3 20.02 18.96 4 20.54 19.82 5 21.06 20.67 6 21.59 21.52 7 22.11 22.37 8 22.63 23.23 9 23.15 24.08 10 23.68 24.93 11 24.20 25.78 12 24.72 26.64 13 25.19 27,41 ** Corrected JANBU FOS = 3.233 ** (Fo factor = 1.070) The following is a summary of the most critical surface Problem Description : FOX MILLER SITE VIEW POP-OUTS BLOCK Modified Correction Initial Terminal Available JANBU FOS Factor x-coord x-coord Strength (ft) (ft) (lb) 1. 3.129 1.037 19.49 24.65 3.271E+03 FOXBL 12-14-«« 14:12 50 ^ 40 . (D 30 00 X < 20 10 FOX MILLER SITE VIEW POP-OUTS BLOCK 10 most critical surfaces, MINIMUM JANBU FOS = 3.129 _ ,w 1 —I , 1 < 1 r— I 1 |— 10 20 30 40 50 X-AXIS (feet) 60 70 80 XSTABL File: FOX 12-14-** 13:48 ****************************************** * XSTABL * * * * Slope Stability Analysis * * using the * * Method of Slices * * * * Copyright (C) 1992. A 95 * * Interactive Software Designs, Inc. * * Moscow, ID 83843, U.S.A. * * * * All Rights Reserved * * * * Ver. 5.103 95 A 1387 * ****************************************** Problem Description : FOX MILLER SITE VIEW POP-OUTS STAB. SEGMENT BOUNDARY COORDINATES 3 SURFACE boundary segments Segment x-left y-left x-right y-right Soil Unit No. (ft) (ft) (ft) (ft) Below Segment 1 .0 20.0 20.0 20.0 1 2 20.0 20.0 20.1 24.0 1 3 20.1 24.0 50.0 44.0 1 ISOTROPIC Soil Parameters 1 Soil unit(s) specified Soil Unit Weight Cohesion Friction Pore Pressure Water Unit Moist Sat. Intercept Angle Parameter Constant Surface No. (pcf) (pcf) (psf) (deg) Ru (psf) No. 1 125.0 130.0 300.0 27.00 .000 .0 1 1 Water surface(s) have been specified Unit weight of water = 62.40 (pcf) Water Surface No. 1 specified by 2 coordinate points ********************************** PHREATIC SURFACE, ********************************** Point x-water y-water No. (ft) (ft) 1 .00 5.00 2 50.00 10.00 A critical failure surface searching method, using a random technique for generating CIRCULAR surfaces has been specified. 100 trial surfaces will be generated and analyzed. 10 Surfaces initiate from each of 10 points equally spaced along the ground surface between x = 16.0 ft and X = 2 0.2 ft Each surface terminates between x = 21.0 ft and X = 2 8.0 ft Unless further limitations were imposed, the minimum elevation at which a surface extends is y = .Oft ***** DEFAULT SEGMENT LENGTH SELECTED BY XSTABL ***** 1.0 ft line segments define each trial failure surface. ANGULAR RESTRICTIONS : The first segment of each failure surface will be inclined within the angular range defined by : Lower angular limit := -45.0 degrees Upper angular limit := (slope angle - 5.0) degrees Factors of safety have been calculated by the : ***** SIMPLIFIED JANBU METHOD ***** The 10 most critical of all the failure surfaces examined are displayed below - the most critical first Failure surface No. 1 specified by 19 coordinate points Point x-surf y-surf No. (ft) (ft) 1 16 . 00 20 . 00 2 16 . 99 19 . 85 3 17 99 19 79 4 18 99 19 84 5 19 98 19 99 6 20 94 20 23 7 21 89 20 57 8 22 79 21 00 9 23 64 21 52 10 24 44 22 13 11 25 17 22 80 12 25 84 23 55 13 26 42 24 36 14 26 92 25 23 15 27 33 26 14 16 27 65 27 09 17 27 87 28 06 18 28 00 29 06 19 28 00 29 29 ** Corrected JANBU FOS = 3.288 ** (Fo factor = 1.078) Failure surface No. 2 specified by 19 coordinate points Point x-surf y-surf No. (ft) (ft) 1 16 00 20 00 2 16 99 19 85 3 17 99 19 79 4 18 99 19 84 5 19 98 19 99 6 20 94 20 23 7 21 89 20 57 8 22 79 21 00 9 "23 64 21 52 10 24 44 22 13 11 25 17 22 81 12 25 84 23 56 13 26 42 24 37 14 26 92 25 23 15 27.33 26.14 16 27.65 27.09 17 27.87 28.07 18 28.00 29.06 19 28.00 29.29 ** Corrected JANBU FOS = 3.289 ** (Fo factor = 1.078) Failure surface No. 3 specified by 19 coordinate points Point x-surf y-surf No. (ft) (ft) 1 16 00 20 00 2 16 99 19 85 3 17 99 19 80 4 18 99 19 84 5 19 98 19 99 6 20 94 20 24 7 21 88 20 58 8 22 79 21 01 9 23 64 21 53 10 24 44 22 13 11 25 17 22 81 12 25 83 23 56 13 26 42 24 37 14 26 92 25 24 15 27 33 26 15 16 27 65 27 10 17 27 87 28 07 18 28 00 29 06 19 28 01 29 29 ** Corrected JANBU FOS = 3.290 ** (Fo factor = 1.078) Failure surface No. 4 specified by 19 coordinate points Point x-surf y-surf No. (ft) (ft) 1 16 00 20 .00 2 16 99 19 85 3 17 99 19 80 4 18 99 19 85 5 19 98 19 99 6 20 94 20 24 7 21 88 20 58 8 22 79 21 01 9 23 64 21 53 10 24 44 22 13 11 25 17 22 81 12 25 83 23 56 13 26 42 24 37 14 26 92 25 24 15 27 33 26 15 16 27.65 27.10 17 27.87 28.07 18 28.00 29.07 19 28.01 29.29 ** Corrected JANBU FOS = 3.290 ** (Fo factor = 1.078) Failure surface No. 5 specified by 19 coordinate points Point x-surf y-surf No. (ft) (ft) 1 16 00 20 00 2 16 99 19 85 3 17 99 19 79 4 18 99 19 84 5 19 97 19 99 6 20 94 20 23 7 21 88 20 57 8 22 79 21 01 9 23 64 21 53 10 24 44 22 13 11 25 17 22 81 12 25 83 23 56 13 26 41 24 37 14 26 91 25 24 15 27 32 26 15 16 27 64 27 10 17 27 85 28 08 18 27 97 29 07 19 27 98 29 27 ** Corrected JANBU FOS = 3.304 ** (Fo factor = 1.078) Failure surface No. 6 specified by 19 coordinate points Point x-surf y-surf No. (ft) (ft) 1 16 00 20 00 2 16 99 19 85 3 17 99 19 80 4 18 99 19 84 5 19 97 19 99 6 20 94 20 24 7 21 88 20 58 8 22 79 21 01 9 23 64 21 54 10 24 43 22 14 11 25 17 22 82 12 25 83 23 57 13 26 41 24 39 14 26 91 25 25 15 27 32 26 17 16 27 63 27 11 17 27.85 28.09 18 21 .Sl 29.08 19 27.97 29.27 ** Corrected JANBU FOS = 3.310 ** (Fo factor = 1.078) Failure surface No. 7 specified by 19 coordinate points Point x-surf y-surf No. (ft) (ft) 1 16 00 20 00 2 16 99 19 85 3 17 99 19 79 4 18 99 19 84 5 19 97 19 99 6 20 94 20 23 7 21 88 20 58 8 22 79 21 01 9 23 64 21 53 10 24 43 22 14 11 25 17 22 82 12 25 83 23 57 13 26 41 24 38 14 26 90 25 25 15 27 31 26 16 16 27 63 27 11 17 27 84 28 09 18 27 96 29 08 19 27 97 29 26 ** Corrected JANBU FOS = 3.313 ** (Fo factor = 1.078) Failure surface No. 8 specified by 19 coordinate points Point x-surf y-surf No. (ft) (ft) 1 16 00 20 00 2 16 99 19 85 3 17 99 19 80 4 18 99 19 84 5 19 97 19 99 6 20 94 20 24 7 21 88 20 58 8 22 78 21 01 9 23 64 21 54 10 24 43 22 14 11 25 16 22 83 12 25 82 23 58 13 26 40 24 39 14 26 90 25 26 15 27 30 26 17 16 27 62 27 12 17 27 83 28 10 18 27.95 29.09 19 27.95 29.25 ** Corrected JANBU FOS = 3.323 ** (Fo factor = 1.078) Failure surface No. 9 specified by 19 coordinate points Point x-surf y-surf No. (ft) (ft) 1 16 00 20 00 2 16 99 19 85 3 17 99 19 80 4 18 99 19 84 5 19 97 19 99 6 20 94 20 24 7 21 88 20 58 8 22 78 21 02 9 23 64 21 54 10 24 43 22 14 11 25 16 22 83 12 25 82 23 58 13 26 40 24 39 14 26 90 25 26 15 27 30 26 18 16 27 61 27 13 17 27 83 28 10 18 27 94 29 10 19 27 94 29 25 ** Corrected JANBU FOS = 3.329 ** (Fo factor = 1.07 8) Failure surface No.10 specified by 19 coordinate points Point x-surf y-surf No. (ft) (ft) 1 16 00 20 00 2 16 99 19 85 3 17 99 19 80 4 18 99 19 84 5 19 97 19 99 6 20 94 20 24 7 21 88 20 58 8 22 78 21 02 9 23 63 21 55 10 24 43 22 15 11 25 16 22 84 12 25 81 23 59 13 26 39 24 41 14 26 88 25 28 15 27 28 26 20 16 27 59 27 15 17 27 80 28 13 18 27 91 29 12 19 27.91 29.22 ** Corrected JANBU FOS = 3.357 ** (Fo factor = 1.078) The following is a summary of the TEN most critical surfaces Problem Description : FOX MILLER SITE VIEW POP-OUTS STAB. Modified Correction Initial Terminal Available JANBU FOS Factor x-coord x-coord Strength (ft) (ft) (lb) 1. 3 288 1 078 16 00 28 00 6 868E+03 2 . 3 289 1 078 16 00 28 00 6 866E+03 3 . 3 290 1 078 16 00 28 01 6 864E+03 4 . 3 290 1 078 16 00 28 01 6 863E+03 5 . 3 304 1 078 16 00 27 98 6 855E+03 6 . 3 310 1 078 16 00 27 97 6 847E+03 7 . 3 313 1 078 16 00 27 97 6 847E+03 8 . 3 323 1 078 16 00 27 95 6 838E+03 9. 3 329 1 078 16 00 27 94 6 834E+03 10 . 3 357 1 078 16 00 27 91 6 815E+03 * * * END OF FILE FOX 12-14-.. 13:47 50 40 _ CD 30 X < 20 >- 10 FOX MILLER SITE VIEW POP-OUTS STAB. 10 most critical surfaces, MINIMUM JANBU FOS = 3.288 —I ' 1 ' 1 ' 1 ' r- 10 20 30 40 50 X-AXIS (feet) —r~ 70 60 80