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REVIEWED RESUB 1-Geotechnical_Letter+12.21.2021GEoTEcx CONSULTANTS, INC- Kevin Keck and Heather Hathaway 538 Battery Street, Apt. 508A Seattle, Washington 98121 via email. kevkeck(c)-me.com Subject: Project Update Proposed Single -Family Residence 15722 — 72"d Avenue West Edmonds, Washington Dear Mr. Keck and Ms. Hathaway: 2401 10th Ave E Seattle, Washington 98102 (425) 747-5618 December 15, 2021 J N 20432 Our firm has initially prepared a geotechnical engineering study for the proposed Meadowview Estates short -plat project, of which the proposed residence project is located within, dated October 9, 2013. In addition, our firm more recently prepared a geotechnical engineering study for a residence project on the property that is very similar from a geotechnical engineering perspective; that study is dated October 16, 2017. More recently, we prepared a letter noted as "Geotechnical Hazard Identification/Declaration and Mitigation Statement of Risk" dated July 14, 2021. When the Meadowdale Estates short -plat was platted, we had determined in 2013 that, based on the code at that time and subsequent slope stability analyses, a 65-foot setback from steep slope on the western side of the Meadowdale Estates was suitable to install conventional footing foundations for residences there. We assumed that this 65-foot-setback continued for any new residences located within Meadowdale Estates. However, based on a recent Third -Party Review of this project, we understand that a new slope stability analysis is needed based on the newest code (2018 IBC). This letter discusses implications of the newest code and notes subsequent needed updates based on the code. A review of the updated project plans based on needed updates is also contained in this update letter. SEISMIC CONSIDERATIONS AND STABILITY ANALYSIS In accordance with the 2018 International Building Code (IBC), the site class within 100 feet of the ground surface is best represented by Site Class Type D (Stiff Soil Class). As noted in the USGS website, the mapped spectral acceleration value for a 0.2 second (S5) and 1.0 second period (S1) equals 1.33g and 0.47g, respectively. Based on this information, a Maximum Credible Earthquake of 0.62g has been determined. Sections 1803.5 of the IBC and 11.8 of ASCE 7 require that other seismic -related geotechnical design parameters (seismic surcharge for retaining wall design and slope stability) include the potential effects of the Design Earthquake. The peak ground acceleration for the Design Earthquake is defined in Section 11.2 of ASCE 7 as two-thirds (2/3) of the MCE peak ground acceleration, or 0.41 g. As noted earlier, we conducted a stability analysis in 2013 that indicated a 65-foot setback was suitable. Unfortunately, because there are new IBC guidelines between now and 2013, there has been a significant increase in the seismic loading requirements for a seismic slope stability analysis; this increased the seismic loading by over 28 percent (.32g to 0.41g). Using this updated seismic Keck/Hathaway JN 20432 December 15, 2021 Page 2 loading, and the same soil parameters used in 2013 (soil conditions at the site have not changed), we have conducted an updated slope stability analysis using the SLOPE/W computer regarding the pre -established setback of 65 feet from the steep western slope. Unfortunately, because of the higher seismic loading, conventional footings are no longer suitable. The new analysis indicates that a deep, pile foundation is needed at the western edge of the residence at the 65-foot setback (another residence to the north of the subject residence was designed in 2017 using prior code with a similar western pile condition because it was located closer to the steep slope than 65 feet — that residence is now constructed). The proposed residence has several western setbacks because of its proposed configuration and the non -linear condition of the top -of -slope. Therefore, we have not only done analyses for the 65- foot setback, but also for a 78-foot setback and 95-foot setback. The analyses obtained indicate that, at the 65-foot and 78-foot setbacks, using 15- and 8-foot-design-height, pile foundation on the western side of proposed residence, static and dynamic safety factors are 1.8 and 1.2. respectively: these safety factors meet or exceed the required safety factors of 1.5 and 1.2. respectively. We have included with this report the cross -sections of the analyses for both the 65- and 78-foot setbacks, as well as the computer output of these analyses. Design recommendations for a 15- and 8-foot-deep pile foundation is given in a subsequent section of this report. We also did an analysis at the 95-foot setback, and it indicates that a typical footing foundation, which will extend at least a few feet below the ground to reach competent bearing soil is suitable. DEEP PILE FOUNDATION RECOMMENDATIONS As noted above, a deep pile foundation is needed on the western side of the residence based on updated stability analyses; we have analyzed three setback scenarios (65 feet, 78 feet, and 95 feet), and the pile foundation is needed for the 65- and 78-foot setbacks. The deep foundation will need to consist of cantilevered, closely -spaced, drilled -concrete piles. Recommendations for the design and construction of this wall are as follows: The piles should be spaced no more than 3 feet edge -to -edge, so that the soil above the theoretical failure plane can arch between the piles if slope instability west of the residences were to occur. The pile wall should be designed for an active soil pressure equal to that pressure exerted by an equivalent fluid with a unit weight of 30 pcf; for the 65-foot and 78- foot setbacks the design height should be 15 and 8 feet, respectively, beginning at the top of existing ground. This active soil pressure should be assumed to act over the center -to - center pile spacing. An ultimate passive soil pressure equal to that pressure exerted by a fluid with a density of 600 pcf will resist the lateral movement of the soldier piles below the 15- or 8-foot depth. For long-term conditions, a safety factor of 1.5 should be applied to the passive soil pressure for the design. The minimum pile length should be 30 feet for a pile wall located 65 feet from the western slope. The piles would be constructed by setting steel H-beams or rebar cages in drilled holes and grouting the spaces between the steel reinforcements and the soil with concrete for the entire height of each drilled hole. We anticipate that the holes could be drilled without casing, but the contractor should be prepared to case the holes or use the slurry method if caving soil is encountered. Excessive ground loss in the drilled holes must be avoided to reduce the potential for settlement of adjacent structures. If water is present in a hole at the time a soldier pile is poured, concrete must be tremied to the bottom of the hole. GEOTECH CONSULTANTS, INC. Keck/Hathaway December 15, 2021 JN 20432 Page 3 The updated information noted above with regards to the new slope analyses and the need for a deep pile foundation has been provided to the project design team over the last few months. This information is now included in updated plans — plans that we have reviewed. We point out that the use of footing foundations on the other portions of the residence are still suitable, and the updated plans also indicate this. The plans we have recently updated and we have reviewed include: 1) Sheets S1.1 through S5.2, which were prepared by SSF Structural Engineering dated November 12, 2021, 2) Sheets C1.1 through C4.2 (which include a TESC plan), which were prepared by CG Engineering dated December 3, 2021, 3) Sheets A001 through A601, which were prepared by Studio Zerby dated December 15, 2021, and 4) Sheets L2.0 through 4.1, which was prepared by Kenneth Philp Landscape Architects dated November 30, 2021. In our professional opinion, the plans are now updated to include provisions noted in the 2018 IBC. We trust that this letter meets your immediate needs for the proposed development. Please contact us if we can be of further service. Attachments: Slope Stability Analysis outputs cc: Studio Zerbey - Kyle Zerbey via email: Kyle(cDstudiozerbey.com DRW:kg Respectfully submitted, GEOTECH CONSULTANTS, INC. D. Robert Ward, P.E. Principal GEOTECH CONSULTANTS, INC. Attachments Slope Stability Analysis JN 20432 Keck and Hathaway 20432 - Keck and Hathaway n-:_ A w Distance (Feet) 11 /24/21, 8:28 AM Static Static Report generated using GeoStudio 2012. Copyright © 1991-2016 GEO-SLOPE International Ltd. File Information File Version: 8.15 Title: 20432 Slope Stability Created By: Matt McGinnis Last Edited By: Matt McGinnis Revision Number: 63 Date: 11/15/2021 Time: 1:47:54 PM Tool Version: 8.15.6.13446 File Name: 20432 Slope Stability - 2021 November 65'.gsz Directory: C:\Users\MattM\OneDrive - Geotech Consultants\Slope Stability Analysis\20432 Keck\ Last Solved Date: 11/15/2021 Last Solved Time: 1:47:54 PM Project Settings Length(L) Units: Feet Time(t) Units: Seconds Force(F) Units: Pounds Pressure(p) Units: psf Strength Units: psf Unit Weight of Water: 62.4 pcf View: 2D Element Thickness: 1 Analysis Settings Static Kind: SLOPE/W Method: Morgenstern -Price Settings Side Function Interslice force function option: Half -Sine PWP Conditions Source: (none) Slip Surface Direction of movement: Right to Left Use Passive Mode: No Slip Surface Option: Fully -Specified Critical slip surfaces saved: 1 Resisting Side Maximum Convex Angle: 1 ° Driving Side Maximum Convex Angle: 5 ° Optimize Critical Slip Surface Location: No Tension Crack Tension Crack Option: (none) F of S Distribution F of S Calculation Option: Constant file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 65' static.html 1/4 11 /24/21, 8:28 AM Static Advanced Number of Slices: 30 F of S Tolerance: 0.001 Minimum Slip Surface Depth: 0.1 ft Search Method: Root Finder Tolerable difference between starting and converged F of S: 3 Maximum iterations to calculate converged lambda: 20 Max Absolute Lambda: 2 Materials Sand Model: Mohr -Coulomb Unit Weight: 135 pcf Cohesion': 200 psf Phi': 42 ° Phi-B: 0 ° Hard Silt and Clay Model: Mohr -Coulomb Unit Weight: 125 pcf Cohesion': 300 psf Phi': 33 ° Phi-B: 0 ° Slip Surface Limits Left Coordinate: (0, 0) ft Right Coordinate: (510, 150) ft Fully Specified Slip Surfaces Fully Specified Slip Surface 1 X (ft) Y (ft) 95 18 114.5 20 132.5 22 155 25 172.5 28.5 196 36.5 211.50021 46 222.5 54.5 233 64 244.5 77 251.5 86 257 94 257 109.08235 file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 65' static.html 2/4 11 /24/21, 8:28 AM Static Seismic Coefficients Horz Seismic Coef.: 0 Points X (ft) Y (ft) Point 1 0 0 Point 2 510 0 Point 3 510 150 Point 4 192 98 Point 5 140 58 Point 6 510 58 Point 7 95 18 Point 8 237 105.7 Point 9 237 85.5 Point 10 305 117.2 Point 11 257 109.08235 Point 12 259 109.42059 Point 13 258 109.25147 Point 14 258.5 109.33603 Regions Material Points Area (ft') Region 1 Hard Silt and Clay 1,2,6,5,7 24,025 Region 2 Sand 8,4,5,6,3,10,12,14,13,11 22,146 Current Slip Surface Slip Surface: 1 F of S: 1.782 Volume: 6,297.4504 ft3 Weight: 822,150.59 Ibs Resisting Moment: 52,513,734 Ibs-ft Activating Moment: 29,462,367 Ibs-ft Resisting Force: 515,069.69 Ibs Activating Force: 288,993.79 Ibs F of S Rank (Analysis): 1 of 1 slip surfaces F of S Rank (Query): 1 of 1 slip surfaces Exit: (95, 18) ft Entry: (257, 94) ft Radius: 102.10049 ft Center: (149.25926, 113) ft Slip Slices X (ft) Y (ft) PWP (psf) Base Normal Stress (psf) Frictional Strength (psf) Cohesive Streng (psf) 300 Slice 1 97.4375 18.25 0 225.46379 146.4179 Slice 2 102.3125 18.75 0 722.14653 468.96744 300 Slice 3 107.1875 19.25 0 1,237.5528 803.67617 300 th file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 65' static.html 3/4 11/24/21, 8:28 AM Static Slice 4 112.0625 19.75 0 1,771.1677 1,150.2098 300 Slice 5 117.5 20.333333 0 2,368.9455 1,538.4112 300 Slice 6 123.5 21 0 3,055.2965 1,984.1328 300 Slice 7 129.5 21.666667 0 3,757.4282 2,440.1024 300 Slice 8 136.25 22.5 0 4,460.3775 2,896.603 300 Slice 9 142.5 23.333333 0 5,139.6476 3,337.7262 300 Slice 147.5 24 0 5,652.156 3,670.553 300 10 Slice 152.5 24.666667 0 6,152.2228 3,995.3002 300 11 Slice 157.91667 25.583333 0 6,242.0708 4,053.6482 300 12 Slice 163.75 26.75 0 6,678.7328 4,337.2198 300 13 Slice 169.58333 27.916667 0 7,090.6072 4,604.6942 300 14 Slice 174.9375 29.329787 0 6,535.9027 4,244.4648 300 15 Slice 179.8125 30.989362 0 6,732.91 4,372.4029 300 16 Slice 184.6875 32.648936 0 6,926.1139 4,497.871 300 17 Slice 189.5625 34.308511 0 7,116.1062 4,621.2534 300 18 Slice 194 35.819149 0 7,141.6115 4,637.8167 300 19 Slice 198.58337 38.083333 0 5,692.7021 3,696.884 300 20 Slice 203.7501 41.25 0 5,477.4444 3,557.094 300 21 Slice 208.91684 44.416667 0 5,274.4549 3,425.2711 300 22 Slice 214.25016 48.125 0 4,600.5126 2,987.6078 300 23 Slice 219.75005 52.375 0 4,382.0182 2,845.7159 300 24 Slice 224.43421 56.25 0 3,919.5698 2,545.3984 300 25 Slice 22g 68421 61 0 3,484.6635 3,137.6051 200 26 Slice 235 66.26087 0 2,859.5687 2,574.7672 200 27 Slice 240.75 72.76087 0 2,515.3271 2,264.8107 200 28 Slice 248 81.5 0 1,899.4335 1,710.2576 200 29 Slice 254.25 90 0 1,317.3955 1,186.1882 200 30 file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 65' static.html 4/4 20432 - Keck and Hathaway w Distance (Feet) 11 /24/21, 8:29 AM Seismic Seismic Report generated using GeoStudio 2012. Copyright © 1991-2016 GEO-SLOPE International Ltd. File Information File Version: 8.15 Title: 20432 Slope Stability Created By: Matt McGinnis Last Edited By: Matt McGinnis Revision Number: 63 Date: 11/15/2021 Time: 1:47:54 PM Tool Version: 8.15.6.13446 File Name: 20432 Slope Stability - 2021 November 65'.gsz Directory: C:\Users\MattM\OneDrive - Geotech Consultants\Slope Stability Analysis\20432 Keck\ Last Solved Date: 11/15/2021 Last Solved Time: 1:47:54 PM Project Settings Length(L) Units: Feet Time(t) Units: Seconds Force(F) Units: Pounds Pressure(p) Units: psf Strength Units: psf Unit Weight of Water: 62.4 pcf View: 2D Element Thickness: 1 Analysis Settings Seismic Kind: SLOPE/W Method: Morgenstern -Price Settings Side Function Interslice force function option: Half -Sine PWP Conditions Source: (none) Slip Surface Direction of movement: Right to Left Use Passive Mode: No Slip Surface Option: Fully -Specified Critical slip surfaces saved: 1 Resisting Side Maximum Convex Angle: 1 ° Driving Side Maximum Convex Angle: 5 ° Optimize Critical Slip Surface Location: No Tension Crack Tension Crack Option: (none) F of S Distribution F of S Calculation Option: Constant file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 65' seismic.html 1/4 11 /24/21, 8:29 AM Seismic Advanced Number of Slices: 30 F of S Tolerance: 0.001 Minimum Slip Surface Depth: 0.1 ft Search Method: Root Finder Tolerable difference between starting and converged F of S: 3 Maximum iterations to calculate converged lambda: 20 Max Absolute Lambda: 2 Materials Sand Model: Mohr -Coulomb Unit Weight: 135 pcf Cohesion': 200 psf Phi': 42 ° Phi-B: 0 ° Hard Silt and Clay Model: Mohr -Coulomb Unit Weight: 125 pcf Cohesion': 300 psf Phi': 33 ° Phi-B: 0 ° Slip Surface Limits Left Coordinate: (0, 0) ft Right Coordinate: (510, 150) ft Fully Specified Slip Surfaces Fully Specified Slip Surface 1 X (ft) Y (ft) 95 18 114.5 20 132.5 22 155 25 172.5 28.5 196 36.5 211.50021 46 222.5 54.5 233 64 244.5 77 251.5 86 257 94 257 109.08235 file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 65' seismic.html 2/4 11 /24/21, 8:29 AM Seismic Seismic Coefficients Horz Seismic Coef.: 0.205 Points X (ft) Y (ft) Point 1 0 0 Point 2 510 0 Point 3 510 150 Point 4 192 98 Point 5 140 58 Point 6 510 58 Point 7 95 18 Point 8 237 105.7 Point 9 237 85.5 Point 10 305 117.2 Point 11 257 109.08235 Point 12 259 109.42059 Point 13 258 109.25147 Point 14 258.5 109.33603 Regions Material Points Area (ft') Region 1 Hard Silt and Clay 1,2,6,5,7 24,025 Region 2 Sand 8,4,5,6,3,10,12,14,13,11 22,146 Current Slip Surface Slip Surface: 1 F of S: 1.207 Volume: 6,297.4504 ft3 Weight: 822,150.59 Ibs Resisting Moment: 48,813,879 Ibs-ft Activating Moment: 40,457,813 Ibs-ft Resisting Force: 491,222.9 Ibs Activating Force: 407,091.49 Ibs F of S Rank (Analysis): 1 of 1 slip surfaces F of S Rank (Query): 1 of 1 slip surfaces Exit: (95, 18) ft Entry: (257, 94) ft Radius: 102.10049 ft Center: (149.25926, 113) ft Slip Slices X (ft) Y (ft) PWP (psf) Base Normal Stress (psf) Frictional Strength (psf) Cohesive Streng (psf) 300 Slice 1 97.4375 18.25 0 231.69513 150.46458 Slice 2 102.3125 18.75 0 768.84219 499.29196 300 Slice 3 107.1875 19.25 0 1,347.9766 875.38624 300 th file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 65' seismic.html 3/4 11/24/21, 8:29 AM Seismic Slice 4 112.0625 19.75 0 1,973.8014 1,281.8016 300 Slice 5 117.5 20.333333 0 2,697.0654 1,751.4948 300 Slice 6 123.5 21 0 3,578.0437 2,323.6087 300 Slice 7 129.5 21.666667 0 4,523.4603 2,937.5695 300 Slice 8 136.25 22.5 0 5,393.5807 3,502.6323 300 Slice 9 142.5 23.333333 0 6,313.9522 4,100.3285 300 Slice 147.5 24 0 7,002.8417 4,547.6986 300 10 Slice 152.5 24.666667 0 7,647.3964 4,966.2773 300 11 Slice 157.91667 25.583333 0 7,105.2439 4,614.1993 300 12 Slice 163.75 26.75 0 7,466.0476 4,848.508 300 13 Slice 169.58333 27.916667 0 7,745.5052 5,029.9899 300 14 Slice 174.9375 29.329787 0 6,023.6201 3,911.7846 300 15 Slice 179.8125 30.989362 0 6,061.7487 3,936.5456 300 16 Slice 184.6875 32.648936 0 6,105.3514 3,964.8616 300 17 Slice 189.5625 34.308511 0 6,159.1353 3,999.7892 300 18 Slice 194 35.819149 0 6,089.9905 3,954.8861 300 19 Slice 198.58337 38.083333 0 4,076.2688 2,647.1599 300 20 Slice 203.7501 41.25 0 3,921.0016 2,546.3282 300 21 Slice 208.91684 44.416667 0 3,796.6378 2,465.5654 300 22 Slice 214.25016 48.125 0 3,164.3845 2,054.9753 300 23 Slice 219.75005 52.375 0 3,085.1728 2,003.5346 300 24 Slice 224.43421 56.25 0 2,729.8849 1,772.808 300 25 Slice 22g 68421 61 0 2,541.5182 2,288.3933 200 26 Slice 235 66.26087 0 2,046.7358 1,842.8892 200 27 Slice 240.75 72.76087 0 1,867.8981 1,681.863 200 28 Slice 248 81.5 0 1,449.6 1,305.2257 200 29 Slice 254.25 90 0 1,030.9036 928.22973 200 30 file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 65' seismic.html 4/4 20432 - Keck & Hathaway 12/1/21, 10:52 AM Static Static Report generated using GeoStudio 2012. Copyright © 1991-2016 GEO-SLOPE International Ltd. File Information File Version: 8.15 Title: 20432 Slope Stability Created By: Matt McGinnis Last Edited By: Matt McGinnis Revision Number: 71 Date: 12/1/2021 Time: 10:44:40 AM Tool Version: 8.15.6.13446 File Name: 20432 Slope Stability - 2021 November 78'.gsz Directory: C:\Users\MattM\OneDrive - Geotech Consultants\Slope Stability Analysis\20432 Keck\ Last Solved Date: 12/1/2021 Last Solved Time: 10:44:41 AM Project Settings Length(L) Units: Feet Time(t) Units: Seconds Force(F) Units: Pounds Pressure(p) Units: psf Strength Units: psf Unit Weight of Water: 62.4 pcf View: 2D Element Thickness: 1 Analysis Settings Static Kind: SLOPE/W Method: Morgenstern -Price Settings Side Function Interslice force function option: Half -Sine PWP Conditions Source: (none) Slip Surface Direction of movement: Right to Left Use Passive Mode: No Slip Surface Option: Fully -Specified Critical slip surfaces saved: 1 Resisting Side Maximum Convex Angle: 1 ° Driving Side Maximum Convex Angle: 5 ° Optimize Critical Slip Surface Location: No Tension Crack Tension Crack Option: (none) F of S Distribution F of S Calculation Option: Constant file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 78' static.html 1/5 12/1/21, 10:52 AM Static Advanced Number of Slices: 30 F of S Tolerance: 0.001 Minimum Slip Surface Depth: 0.1 ft Search Method: Root Finder Tolerable difference between starting and converged F of S: 3 Maximum iterations to calculate converged lambda: 20 Max Absolute Lambda: 2 Materials Sand Model: Mohr -Coulomb Unit Weight: 135 pcf Cohesion': 200 psf Phi': 42 ° Phi-B: 0 ° Hard Silt and Clay Model: Mohr -Coulomb Unit Weight: 125 pcf Cohesion': 300 psf Phi': 33 ° Phi-B: 0 ° Slip Surface Limits Left Coordinate: (0, 0) ft Right Coordinate: (510, 150) ft Fully Specified Slip Surfaces Fullv Specified Slip Surface 1 X (ft) Y (ft) 95 18 114.5 20 132.5 22 155 25 172.5 28.5 196 36.5 213 44.5 225.5 54 238 63 249 74 266.5 95 270.5 104 270.5 111.5 file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 78' static.html 2/5 12/1/21, 10:52 AM Static Seismic Coefficients Horz Seismic Coef.: 0 Points X (ft) Y (ft) Point 1 0 0 Point 2 510 0 Point 3 510 150 Point 4 192 98 Point 5 140 58 Point 6 510 58 Point 7 95 18 Point 8 237 105.7 Point 9 237 85.5 Point 10 305 117.2 Point 11 259 109.42059 Point 12 258 109.25147 Point 13 258.5 109.33603 Regions Material Points Area (ft2) Region 1 Hard Silt and Clay 1,2,6,5,7 24,025 Region 2 Sand 8,4,5,6,3,10,11,13,12 22,146 Current Slip Surface Slip Surface: 1 F of S: 1.809 Volume: 6,810.3462 ft3 Weight: 890,728.12 Ibs Resisting Moment: 64,352,880 Ibs-ft Activating Moment: 35,565,308 Ibs-ft Resisting Force: 562,180.44 Ibs Activating Force: 310,712.62 Ibs F of S Rank (Analysis): 1 of 1 slip surfaces F of S Rank (Query): 1 of 1 slip surfaces Exit: (95, 18) ft Entry: (270.5, 104) ft Radius: 113.75447 ft Center: (151.14316, 125.5) ft Slip Slices X (ft) Y (ft) PWP (psf) Base Normal Stress (psf) Frictional Strength (psf) Cohesive Strength (psf) Slice 1 98.25 18.333333 0 306.19996 198.84858 300 Slice 2 104.75 19 0 971.07357 630.62255 300 Slice 3 111.25 19.666667 0 1,665.1903 1,081.3872 300 Slice 4 117.5 20.333333 0 2,341.6739 1,520.7008 300 file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 78' static.html 3/5 1211/21, 10:52 AM Static Slice 5 123.5 21 0 3,015.806 1,958.4873 300 Slice 6 129.5 21.666667 0 3,705.7371 2,406.5338 300 Slice 7 136.25 22.5 0 4,403.1248 2,859.4227 300 Slice 8 142.5 23.333333 0 5,077.8772 3,297.612 300 Slice 9 147.5 24 0 5,591.5536 3,631.1974 300 Slice 152.5 24.666667 0 6,097.9024 3,960.0241 300 10 Slice 157.91667 25.583333 0 6,220.9658 4,039.9424 300 11 Slice 163.75 26.75 0 6,677.5729 4,336.4666 300 12 Slice 169.58333 27.916667 0 7,115.7489 4,621.0214 300 13 Slice 175.75 29.606383 0 6,637.8723 4,310.6847 300 14 Slice 182.25 31.819149 0 6,921.1037 4,494.6173 300 15 Slice 188.75 34.031915 0 7,198.5764 4,674.8102 300 16 Slice 194 35.819149 0 7,274.0504 4,723.8236 300 17 Slice 198.83333 37.833333 0 6,419.1247 4,168.6283 300 18 Slice 204.5 40.5 0 6,210.1688 4,032.9308 300 19 Slice 210.16667 43.166667 0 6,008.9434 3,902.2535 300 20 Slice 216.125 46.875 0 4,784.9075 3,107.3553 300 21 Slice 222.375 51.625 0 4,520.8157 2,935.8521 300 22 Slice 228 27778 56 0 4,384.5206 2,847.341 300 23 Slice 234.02778 60.14 0 3,999.0233 3,600.7367 200 24 Slice 237.5 62.64 0 3,837.001 3,454.8512 200 25 Slice 240.75 65.75 0 3,128.7086 2,817.1018 200 26 Slice 246.25 71.25 0 2,818.3285 2,537.6344 200 27 Slice 251.25 76.7 0 2,287.1983 2,059.4026 200 28 Slice 255.75 82.1 0 1,984.422 1,786.7816 200 29 Slice 258.25 85.1 0 1,811.2065 1,630.8176 200 30 Slice 258.75 85.7 0 1,775.9242 1,599.0493 200 31 Slice 262.75 90.5 0 1,484.8293 1,336.9463 200 32 Slice 268.5 99.5 0 600.2183 540.43899 1 200 file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 78' static.html 4/5 1211/21, 10:52 AM Static 1 33 1 1 1 1 1 1 1 file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 78' static.html 5/5 20432 - Keck & Hathaway n_:___:_ n__i. -:_ Distance (Feet) 1211121, 10:49 AM Seismic Seismic Report generated using GeoStudio 2012. Copyright © 1991-2016 GEO-SLOPE International Ltd. File Information File Version: 8.15 Title: 20432 Slope Stability Created By: Matt McGinnis Last Edited By: Matt McGinnis Revision Number: 71 Date: 12/1/2021 Time: 10:44:40 AM Tool Version: 8.15.6.13446 File Name: 20432 Slope Stability - 2021 November 78'.gsz Directory: C:\Users\MattM\OneDrive - Geotech Consultants\Slope Stability Analysis\20432 Keck\ Last Solved Date: 12/1/2021 Last Solved Time: 10:44:41 AM Project Settings Length(L) Units: Feet Time(t) Units: Seconds Force(F) Units: Pounds Pressure(p) Units: psf Strength Units: psf Unit Weight of Water: 62.4 pcf View: 2D Element Thickness: 1 Analysis Settings Seismic Kind: SLOPE/W Method: Morgenstern -Price Settings Side Function Interslice force function option: Half -Sine PWP Conditions Source: (none) Slip Surface Direction of movement: Right to Left Use Passive Mode: No Slip Surface Option: Fully -Specified Critical slip surfaces saved: 1 Resisting Side Maximum Convex Angle: 1 ° Driving Side Maximum Convex Angle: 5 ° Optimize Critical Slip Surface Location: No Tension Crack Tension Crack Option: (none) F of S Distribution F of S Calculation Option: Constant file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 78' seismic.html 1/5 12/1/21, 10:49AM Seismic Advanced Number of Slices: 30 F of S Tolerance: 0.001 Minimum Slip Surface Depth: 0.1 ft Search Method: Root Finder Tolerable difference between starting and converged F of S: 3 Maximum iterations to calculate converged lambda: 20 Max Absolute Lambda: 2 Materials Sand Model: Mohr -Coulomb Unit Weight: 135 pcf Cohesion': 200 psf Phi': 42 ° Phi-B: 0 ° Hard Silt and Clay Model: Mohr -Coulomb Unit Weight: 125 pcf Cohesion': 300 psf Phi': 33 ° Phi-B: 0 ° Slip Surface Limits Left Coordinate: (0, 0) ft Right Coordinate: (510, 150) ft Fully Specified Slip Surfaces Fullv Specified Slip Surface 1 X (ft) Y (ft) 95 18 114.5 20 132.5 22 155 25 172.5 28.5 196 36.5 213 44.5 225.5 54 238 63 249 74 266.5 95 270.5 103.5 270.5 111.5 file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 78' seismic.html 2/5 12/1/21, 10:49AM Seismic Seismic Coefficients Horz Seismic Coef.: 0.205 Points X (ft) Y (ft) Point 1 0 0 Point 2 510 0 Point 3 510 150 Point 4 192 98 Point 5 140 58 Point 6 510 58 Point 7 95 18 Point 8 237 105.7 Point 9 237 85.5 Point 10 305 117.2 Point 11 259 109.42059 Point 12 258 109.25147 Point 13 258.5 109.33603 Regions Material Points Area (ft2) Region 1 Hard Silt and Clay 1,2,6,5,7 24,025 Region 2 Sand 8,4,5,6,3,10,11,13,12 22,146 Current Slip Surface Slip Surface: 1 F of S: 1.207 Volume: 6,811.3462 ft' Weight: 890,863.12 Ibs Resisting Moment: 59,291,075 Ibs-ft Activating Moment: 49,136,295 Ibs-ft Resisting Force: 533,358.77 Ibs Activating Force: 441,957.92 Ibs F of S Rank (Analysis): 1 of 1 slip surfaces F of S Rank (Query): 1 of 1 slip surfaces Exit: (95, 18) ft Entry: (270.5, 103.5) ft Radius: 113.26283 ft Center: (151.50962, 124.875) ft Slip Slices X (ft) Y (ft) PWP (psf) Base Normal Stress (psf) Frictional Strength (psf) Cohesive Strength (psf) Slice 1 98.25 18.333333 0 316.30529 205.41105 300 Slice 2 104.75 19 0 1,039.2671 674.90791 300 Slice 3 111.25 19.666667 0 1,832.7325 1,190.1904 300 Slice 4 117.5 20.333333 0 2,636.5897 1,712.2214 300 file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 78' seismic.html 3/5 1211/21, 10:49AM Seismic Slice 5 123.5 21 0 3,486.0923 2,263.8948 300 Slice 6 129.5 21.666667 0 4,397.5196 2,855.7826 300 Slice 7 136.25 22.5 0 5,255.5976 3,413.025 300 Slice 8 142.5 23.333333 0 6,168.3699 4,005.7863 300 Slice 9 147.5 24 0 6,869.7346 4,461.2578 300 Slice 152.5 24.666667 0 7,548.1071 4,901.798 300 10 Slice 157.91667 25.583333 0 7,119.2747 4,623.3111 300 11 Slice 163.75 26.75 0 7,556.6782 4,907.3642 300 12 Slice 169.58333 27.916667 0 7,929.0141 5,149.162 300 13 Slice 175.75 29.606383 0 6,262.3899 4,066.8436 300 14 Slice 182.25 31.819149 0 6,356.5269 4,127.9769 300 15 Slice 188.75 34.031915 0 6,453.3362 4,190.8456 300 16 Slice 194 35.819149 0 6,408.8897 41161.9816 300 17 Slice 198.83333 37.833333 0 5,076.6091 3,296.7885 300 18 Slice 204.5 40.5 0 4,864.6151 3,159.118 300 19 Slice 210.16667 43.166667 0 4,681.8709 3,040.4425 300 20 Slice 216.125 46.875 0 3,280.7777 2,130.5619 300 21 Slice 222.375 51.625 0 3,151.7905 2,046.7967 300 22 Slice 228 27778 56 0 3,166.0448 2,056.0535 300 23 Slice 234.02778 60.14 0 3,031.9293 2,729.9614 200 24 Slice 237.5 62.64 0 2,934.6845 2,642.4018 200 25 Slice 240.75 65.75 0 2,240.7683 2,017.5969 200 26 Slice 246.25 71.25 0 2,073.482 1,866.9716 200 27 Slice 251.25 76.7 0 1,665.9161 1,499.9976 200 28 Slice 255.75 82.1 0 1,484.1298 1,336.3165 200 29 Slice 258.25 85.1 0 1,374.7411 1,237.8224 200 30 Slice 258.75 85.7 0 1,351.7868 1,217.1543 200 31 Slice 262.75 90.5 0 1,153.19 1,038.337 200 32 Slice 268.5 99.25 0 455.67706 410.29347 1 200 file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 78' seismic.html 4/5 1211/21, 10:49AM Seismic 1 33 1 1 1 1 1 1 1 file:///C:/Users/MattM/onedrive - geotech consultants/slope stability analysis/20432 keck/20432 slope stability - 2021 november 78' seismic.html 5/5