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HomeMy WebLinkAboutCDP 02-42; 2200 HIGHLAND DR; RESPONSE TO CITY REVIEW OF GEOTECHNICAL INVESTIGATION; 1991-03-04March 4, 1991 KarenBlumenshine P.O. Box 850 Carpenteria, California 93013 SUBJECT: RESPONSE TO CITY REVIEW Minor Subdivision No. 818 Carlsbad, California Reference: City of Carlsbad, January 30, 1991, Review of Grading plans Ron Gutier, Erik J. Nelson, February 17, 1989, "Geotechnical Investigation, Proposed Lot Split, Three-Acre Site, 2202 Highland Drive, Carlsbad, California" Dear Karen: I have received the city engineers comments regarding my review of the grading plans. My review of the plans indicates that the plans shown are in conformance with the intent of the recommendations of the referenced report. Some minor differences do exist as outlined in the city's response. I. The slopes shown are steeper than was recommended in the original report. The recommendations presented in that report were purposefully conservative to allow for some flexibility in the design process. In addition the full height of the slope is achieved by using two smaller 2:1 slopes which result in an overall top to bottom slope ratio of 2.3:1. I have performed additional calculations on the slope as shown and have obtained a factor of safety of 1.5. Copies of the calculations are included attached to this report. 2. The city does not feel that the map shows the removal of all unsuitable fill soils. It is my opinion that reconstruction of the storm drain will result in the replacement of all uncompacted fills in the main canyon area. No new fill should be placed over previously uncompacted fill, and all new fills placed against slopes need to be benched into competent soil or bedrock. This recommendation includes any fill soils located below or over the new stormdrain pipe. Uncompacted fill soils may still remain in other areas of the site but are not expected to have an effect on the planned structures. There is a possibility that a minor amount of unsuitable fill will be encountered in the eastern building area once it has been cut to the proposed grade. Since the majority of this area is expected to be in bedrock cut, any fill soils left should be minor amounts which can be easi•y removed and replaced during grading operations. 3. The proposed grading plan shows a 1 percent typical drainage for the site instead of the 2 percent recommended in the report. Due to the relatively high permeability and non expansive nature of the. on-site soils, a one percent slope should be sufficient. i i I '. ' ' ; .. ' f, . I ! I 1:/·:: Karen Blumenshine Subdivision No. 818 March 4, 1991 Page 2 This opportunity to be of service has been appreciated. Should any questions arise or if further services are necessary please feel free to contact me at your convenience.· Respectfully yours, Erik J. Nelson, P.E. C 44102 Registration Expires: 6-30-93 Civil Engineer Run Date: ** PCSTABL5 ** by Purdue University --Slope Stability Analysis-- Simplified Janbu, Simplified Bishop or Spencer's Method of Slices 12-27-90 Time of Run: 6: 17 Run By: Input Data Filename: 01.1tput Filename: EJN SECTZ-Z' SECTZ-Z'.OUT PROBLEM DESCRIPTION SECTION Z-Z', KAREN BLUMENSHINE, LOT SPL IT BOUNDARY COORDINATES 6 Top Boundaries 10 Total Boundaries Boundary X-Left Y-Left X-Right Y-Right Soil Type N,::i. (ft) (ft) (ft) (ft) Belc,w Bnd 1 .01 7 4. 12)12) 32. 00 80.00 3 2 32.00 80.00 '34. 00 110. 00 1 3 94.00 110. 012) 106.00 110. 00 1 4 106.00 110.00 1 '35. 00 150. 00 1 5 195. 012) 150.00 254.00 150.00 1 6 254.00 150.00 350.00 150.00 2 7 32.00 80. 00 102. 12)0 90.00 3 8 102.00 90.00 250.00 134.00 3 9 250. 00 134. 00 254.00 150.00 2 10 250.00 134.00 350.00 134.00 3 ISOTROPIC SOIL PARAMETERS 3 TypeCs> of Soil Soil Total Saturated C,::ihesion FYiction Pore Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No. 1 120.0 125.0 50.0 28.0 .00 .0 1 2 120.0 125. 0 140. 0 2'3.0 . 12)12) .0 1 3 120.0 125.0 .0 34.0 .00 .0 1 ' !.. !' -: ' • I .• l:f;~ I [· I ' I , .. · •:, 100 Trial Surfaces Have Been Generated. 10 Surfaces Initiate From Each Of 10 Points Equally Spaced Along The Ground Surface Between X = 10.00 ft. and X = 60.00 ft. Each Surface Terminates Between and X = 200.00 ft. X = 250.00 ft. Unless Further Limitations Were Imposed, The Minimum Elevation At Which A Surface Extends Is Y = .00 ft. 17.50 ft. Line Segments Define Each Trial Failure Surface. Following Are Displayed The Ten Most Critical Of The Trial Failure Surfaces Examined. They Are Ordered -Most Critical First. **Safety Factors Are Calculated By The Modified Janbu Method** Failure Surface Specified By 12 Coordinate Points Point Ni:,. l •':I ..:.. 3 4 5 6 7 8 9 10 11 12 X-Surf (ft) 43.33 60.65 77.83 94.81 111.57 128.05 144.22 160.03 175.45 1 '30. 44 204. '36 207.95 Y-Surf (ft) 85.48 87. '38 91.34 '35. 55 100.61 106. 4'3 113.19 120.68 128.96 137. 9,3 147.76 150.00 *** 1.463 *** ~L-<Y ~, /.!? c'A(%1K "''~ >)l'-,~s #~,~. Failure Surface Specified By 12 Coordinate Points t P,:iint X-Surf Y-S1.1r f N,::i. (ft) (ft) 1 43.33 85.48 2 60.56 88.58 3 77.63 92.41 ,::, .. 1 ,:::r:, ,:,c ,::,c: j. L· .. >. ..J J. J. J. .... ....., ,J. .:.;...:.. .. ---. 6 127.68 108.17 7 143.86 114.83 8 159.75 122.16 9 175.31 130.17 10 1'30. 52 138.82 11 205.35 148.12 12 208. 0'3 150. (2)0 *** 1. 473 *** Failure Surface Specified By 11 Coordinate Points Point X-Surf Y-81.lrf Ne,. (ft) (ft) 1 60.00 '33. 55 2 77.50 93.86 3 '34. 90 '35. 68 4 112.08 9'3. 01 5 128. ':H 103.81 6 145.26 110.05 7 161.01 117.68 8 176.04 126.65 '3 1 '30. 23 136. 8'3 10 203.48 148.32 11 205.13 150.00 *** 1.476 *** Failure 81.lrface Specified By 13 Coordinate Points Point X-Surf Y-Surf No. (ft) (ft) 1 ":):.■:• --:---, .,;/.L.■44 80.11 2 49.58 82.35 3 66.82 85.37 4 83.90 8'3. 15 5 100.80 "93. 69 6 117. 4'3 98. '37 7 133.92 1(2)4.99 8 150.07 111. 74 9 165.90 119.1'~ 10 181.38 127.35 11 196.49 136.18 1•") ..:.. 211. 19 145.68 13 217.26 150.00 *** 1.47'3 *** Failure Surface Specified By 12 Coordinate Points i • I I I• I • I .. ; . ! l::· .• Point X-Surf Y-Surf ► Ne:•. (ft) (ft) 1 48.89 88.17 2 66.39 88.03 3 83.85 8'3. 26 4 101.15 91.86 5 118.20 95.82 6 134.88 101. 11 7 151. 0'3 107.70 8 166.74 115.54 '3 181. 71 124.59 10 1'35. 93 134.79 11 209.31 146.(2)8 1.-, .::.. 213.27 150.00 *** 1. 4"32 "*** Failure Surface Specified By 13 Coordinate Points Pciint X-Surf Y-Surf Ne,. (ft) (ft) 1 43.33 85.48 2 60.62 88.19 3 77.80 '31.55 4 94.84 95.54 5 111. 72 100.16 6 128.41 105.41 7 144.90 111.28 8 161.15 117.76 '3 177. 15 124.84 10 192.88 1?·-:• t::'.•") \J..:.... ;:.J..:.. 11 208.31 140.77 1.-, .::.. 2:23.42 149.60 13 224.05 150.00 *** 1. 545 *** Failure Surface Specified By 12 Coordinate Points Point X-Surf Y-Surf No. (ft) (ft) 1 43.33 85.48 2 60.83 85.13 3 78.2'3 86.25 4 ·35.60 88.82 5 112. 63 '32. 85 6 129.27 98.29 7 145.38 105.11 8 160.87 113.26 '3 175.62 122.68 10 18"3. 52 133.30 11 202.49 145.(2)6 • -""•-r ........ .--... ~ l""I "''I ·. •:-: :: :-:-·- .=~ i);:: £;.?.'.(;- • . I '·.:. *** 1.548 *** Failure Surface Specified By 11 Coordinate Points P,::iint X-Surf Y-Surf Ni:,. (ft) ( ft:> 1 60.00 '33. 55 2 77.36 95.76 3 94. 5•9 '38. 81 4 111.66 112!2. 7121 5 128.51 107.41 6 145.11 112.94 7 161.43 119.27 8 177.41 126.39 ':J 193.04 134.27 10 208.26 142.'31 11 21 '3. 44 150.00 *** 1.557 *** Failure Surface Specified By 13 Coordinate Points P,::iint X-Surf Y-Surf No. (ft) (ft) 1 37.78 82.80 2 55.25 83.74 3 72.65 85.61 4 89.93 88.40 5 107 .1214 '32. 0'3 6 123.92 96.68 7 140.54 102.16 8 156.85 108. 512) '3 172.80 115.70 1121 188.35 123.73 11 203.46 132.57 12 218.08 142.19 13 228.68 150. 00 *** 1.571 *** Failure Surface Specified By 14 Coordinate Points Point X-Surf Y-Surf N,::i. (ft) (ft) 1 15.56 76.92 2 33.04 76.23 3 50. 53 76.83 4 67. '33 78. 6'3 = --., --. -- i L-1 .. •'· .,,:,• l I c:., J."-'-• .L~ Wua 7 118.68 91.79 8 134.81 '98. 58 9 150.40 106.52 10 165.37 115.58 11 17'3. 64 125.71 12 193.14 136.85 13 205.79 148.94 14 :206.75 150.00 *** 1.628 *** y A X I s F T .00 43.75 87.50 131.25 175.00 218.75 X .00 +---------+------*--+---------+---------+---------+ 43.75 + A 87.50 + . . X 131.25 + I 175.00 + s 218.75 + 262.512) + F 306.25 + . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IZ) 1 . 045 . . . 713 0.4 . . 9 .518. .04 ... 7.18.* .0* . • .7 1 * .054 . . • . '3 . . . . .7512 . . . . . . . • • • • • • . • •3 ....... 731 .054 . . . . . . . . . 9731. . . . . . . . . . . . . . . . 54 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 712 . . . . 54 . . .9.631 • • 4. * . 9 .. 71 . . . . . . . .641 .. 94 .6 . . . . . . . . . . . . . * !· .. 1· ::·.:;•: ..... ...... 1.-· t/i .. :: ... R•.tn Date: ** PCSTABL5 ** by Purdue University --Slope Stability Analysis-- Simplified Janbu, Simplified Bishop or Spencer~s Method of Slices 12-27-'30 Time c,f Run: 6:26 Run By: Inpµt Data Filename: O•.ttput Filename: EJN SECTZ-Z' SECTZ-Z'.OT2 PROBLEM DESCRIPTION SECTION Z-Z', KAREN BLUMENSHINE, LOT SPL I T., .!7/&,?~ #e-bt-,.-L. BOUNDARY COORDINATES 6 Top Boundaries 10 Total B,::iundaries Boundary X-Left Y-Left X-Right Y-Right Soil Type N,:,. (ft) (ft) (ft) (ft) Below Bnd 1 .01 74.00 32. 00 80.00 3 2 32.00 80.00 94. 00 110.00 1 3 94.00 110.00 106.00 1112). 00 1 4 106.00 110. 00 1'35. 00 150.00 1 5 1'35. 00 150. 00 254.00 150.00 1 6 254.00 150.00 350.00 150.00 2 7 32.00 80. 00 102.00 90. 00 3 8 102.00 '30. 00 250.00 134.00 3 9. 250.00 134. 12)12) 254.00 150.00 2 10 250.00 134.00 350.00 134.00 3 ISOTROPIC SOIL PARAMETERS 3 Type(s) of Soil Scail Total Saturated Cohesion Frictic,n P,::ire Pressure Piez. Type Unit Wt. Unit Wt. Intercept Angle Pressure c,:,nstant Surface No. (pcf) (pcf) (psf) (deg) Param. (psf) No. 1 120.0 125.0 50.0 28.0 .00 .0 1 2 120. 0 125.0 140.0 29.0 .00 .0 1 3 120.0 125.0 .0 34.0 .00 .0 1 i;f} •' .. L : • ,·· !· .··• ' i· ! I j. ' Point X-Surf Y-Surf No. (ft) (ft) 1 43.33 85.48 2 60.65 87.98 3 77.83 ':H. 34 4 '34. 81 95.55 5 111.57 100.61 ! • 6 128.05 106. 4'3 7 144.22 113. 1'3 8 160.03 120.68 '3 175.45 128.96 10 190.44 137. 9'3 [• ... .. 11 204. '36 147.76 r 12 207. '35 150.00 '. ,. f Spencer's FOS FOS r~'.tr. Theta C:Mc•ment) <:Force) I.•: (deg) (Eqr.ti 1. ) C:Equil.) 12.50 1. 641 1. 477 18.75 1.554 1.484 24.89 1. 250 1. 4'32 20.58 1. 506 1. 487 19.57 1. 535 1.485 21. 77 1.463 1.488 20.77 1.500 1.487 20.88 1. 4'36 1. 487 21.14 1. 487 1.487 Factor Of Safety F,:,r The Preceding Specified Sr.tr face =~ Spencer's Theta = 21. 14 ,-,:Jt.Me,L Vf" 6, /. 5 ~ Factor Of Safety Is Calculated By Spencer's Methc•d C•f Slices *** Line of Thrust *** Slice X y Side F,::irce N,::i. C•::iord. Cc,ord. L/H ( 1 bs) 1 60.65 90.08 .357 2100. 2 77.83 94.36 . 278 5708 . 3 94.00 '3'3. 07 . 254 9075 . 4 '34. 81 '39. 31 . 260 9264 . 5 106.00 103.10 .377 10608. 6 111.57 105.01 .370 11231. 7 128.05 111. 14 .346 11841. 8 144.22 117.71 .323 11040. 9 160.03 124.73 . 298 8928 . 10 175.45 132.22 . 266 5846 . 11 190.44 140.37 .2313 2403. 1•";• .... 1 '35. 00 143.27 .247 1286 . 13 204.96 160.23 5.566 19. 14 207. '35 160.17 .000 20. I y A X I s F T I .00 43.75 87.50 131.25 175. (2)(2) 218.75 X .00 +---------+------*--+---------+---------+---------+ * 43.75 + s s s A 87.50 + s * * s * X '131.25 + s s s I 175.00 + s 218.75 + 262.50 + F 306.25 + T 350.00 + **************iHE-************************* ****** STOP -Illegal Command ****** ***************************************** Legal Commands -PROFIL LOADS TIES WATER SURFAC EXECUT s s * s s * * * * ::>•:i,; ._•;.,:, wWJ.L RANDOM CIRCLE CIRCL2 BLOCK BLOCK2 LIMITS ANISO SURBIS SPENCR i I i ! ' [,, ,: I· . I • • • '.t ',' I ; I I I I I I i l I I I I ! 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