2025 06 18 WEH Slope Stability Analysis Letter Report

Color Name Unit Weight (pcf) Color Name Unit Weight Bedrock Effective Cohesion (psf) 180 (pcf) Decomposed 135 180 Bedrock Rock/Very Dense Granular Soil Decomposed 135 660 Effective Cohesion (psf) Rock/Very Dense Granular Soil Medium sand 120 Medium sand 150 Topsoil 115 115 Topsoil Effective Friction Angle (°) 38 0 38 0 32 0 120 Retaining Wall Retaining Wall 0 Effective Friction Angle (°) UCS Intact (psf) Intact Rock Parameter mi Geological Strength Index GSI Disturbance Factor D UCS Intact Rock Intact Parameter 17 (psf)323,263 mi Geological Disturbance Strength Factor D Index GSI 65 Piezometric Surface 323,263 65 1 17 1 1 1 32 1 1 1 1 30 30 640 1 1 150 00 Piezometric Surface 1 1 1.589 620 Factor of Safety: 1.589 Current Slip Surface Number: 401 NLB-2 NTP-1 Critical Failure Surface (CFS) 600 NTP-2 NLB-1 Property Line Elevation 580 560 540 520 500 480 460 440 0 100 200 Distance Cross Section D_Existing Condition Cr 300 400

Color Color Name Unit Weight (pcf) Name Unit Weight (pcf) Bedrock 660 180 Effective Cohesion (psf) Effective Cohesion (psf) Decomposed Bedrock 180 135 Rock/Very Dense Decomposed 135 0 Granular Soil 0 Medium sand 0 Rock/Very Dense Granular Soil Medium sand Retaining Wall 120 120 Effective Friction Angle (°) Effective Friction Angle (°) UCS Intact (psf) Intact Rock Parameter mi UCS Intact (psf) Intact Rock Parameter mi Geological Strength Index GSI Disturbance Factor D 17 65 1 38323,263 323,263 17 Geological Strength Index GSI 0 150 Topsoil Topsoil 115 115 0 1 1 1 1 38 1 32 1 32 1 1 1 0 30 640 Piezometric Surface Piezometric Surface 65 150 Retaining Wall Disturbance Factor D 30 1 1 1.589 620 NLB-2 NTP-1 Critical Failure Surface (CFS) 600 Factor of Safety: 1.589 Current Slip Surface Number: 401 NTP-2 NLB-1 Property Line Elevation 580 560 540 520 500 480 460 440 0 100 200 Distance Cross Section D_Proposed Condition Cr 300 400

Cross Section D (Static Condition)

Color 660 Name Unit Weight (pcf) Effective Cohesion (psf) Effective Friction Angle (°) UCS Intact (psf) Intact Rock Geological Parameter Strength mi Index GSI Disturbance Factor D 323,263 17 1 65 Piezometric Surface Bedrock 180 Decomposed Rock/Very Dense Granular Soil 135 0 38 1 1 Dense to Very Dense Sand 125 0 34 1 Medium sand 120 0 32 1 Topsoil 115 0 30 1 640 1.936 620 Factor of Safety: 1.936 Current Slip Surface Number: 396 NLB-4 600 Critical Failure Surface (CFS) R-4B 580 Elevation NLB-3 560 Property Line 540 520 500 480 460 440 0 100 200 Distance Cross Section D_Existing Condition 300 400

Color 660 Name Unit Weight (pcf) Effective Cohesion (psf) Effective Friction Angle (°) UCS Intact (psf) Intact Rock Geological Parameter Strength mi Index GSI Disturbance Factor D Piezometric Surface Bedrock 180 323,263 17 1 1 Decomposed Rock/Very Dense Granular Soil 135 0 38 1 Dense to Very Dense Sand 125 0 34 1 65 Medium sand 120 0 32 1 Topsoil 115 0 30 1 640 1.936 Proposed Building 620 Factor of Safety: 1.936 Current Slip Surface Number: 396 NLB-4 600 Critical Failure Surface (CFS) R-4B 580 Elevation NLB-3 560 Property Line 540 520 500 480 460 440 0 100 200 Distance Cross Section D_Proposed Condition 300 400

APPENDIX F RESULTS OF LEM ANALYSIS FOR SEISMIC CONDITION = = =

Cross Section A (Seismic Condition)

Color 690 Name Slope Stability Material Model Bedrock Hoek-Brown 180 Decomposed Rock/Very Dense Granular Soil Mohr-Coulomb 135 0 38 Dense to Very Dense Mohr-Coulomb Sand 125 0 34 Medium Dense Sand Mohr-Coulomb 120 0 32 Top Soil 115 0 30 Mohr-Coulomb Unit Weight (pcf) Effective Effective UCS Cohesion Friction Intact (psf) Angle (psf) (°) Intact Geological Disturbance Piezometric Rock Strength Factor D Surface Parameter Index GSI mi 323,263 17 65 1 1 1 1.651 640 TP-1 Criticalsurface Failure Failure Surface (CFS) TP-8 LB-1 TP-2 590 Factor of Safety: 1.651 Current Slip Surface Number: 327 Horz Seismic Coef.: 0.0875 TP-3 540 LB-2 Approximate location of Existing Building Elevation 490 440 390 340 290 240 190 0 100 200 300 400 500 600 700 Distance Cross Section A_Existing Condition 800 900 1,000 1,100 1,200

Color Proposed Building D.1 690 Name Slope Stability Material Model Bedrock Hoek-Brown 180 Decomposed Rock/Very Dense Granular Soil Mohr-Coulomb 135 0 38 Dense to Very Dense Mohr-Coulomb Sand 125 0 34 Medium Dense Sand Mohr-Coulomb 120 0 32 Top Soil 115 0 30 Mohr-Coulomb Unit Weight (pcf) Effective Effective UCS Cohesion Friction Intact (psf) Angle (psf) (°) Intact Geological Disturbance Piezometric Rock Strength Factor D Surface Parameter Index GSI mi 323,263 17 65 1 1 1 1.649 640 Criticalsurface Failure Failure Surface (CFS) TP-8 LB-1 8.2753 ft TP-1 TP-2 590 Factor of Safety: 1.649 Current Slip Surface Number: 327 Horz Seismic Coef.: 0.0875 TP-3 540 LB-2 Approximate location of Existing Building Elevation 490 440 390 340 290 240 190 0 100 200 300 400 500 600 700 Distance Cross Section A_Proposed Condition 800 900 1,000 1,100 1,200

Color 690 Name Slope Stability Material Model Bedrock Hoek-Brown 180 Decomposed Rock/Very Dense Granular Soil Mohr-Coulomb 135 0 38 Dense to Very Dense Mohr-Coulomb Sand 125 0 34 Medium Dense Sand Mohr-Coulomb 120 0 32 Top Soil 115 0 30 Mohr-Coulomb Unit Weight (pcf) Effective Effective UCS Cohesion Friction Intact (psf) Angle (psf) (°) Intact Geological Disturbance Piezometric Rock Strength Factor D Surface Parameter Index GSI mi 323,263 17 65 1 1 1 2.234 640 TP-1 Critical Failure Failure surface Surface (CFS) TP-8 LB-1 TP-2 590 Factor of Safety: 2.234 Current Slip Surface Number: 221 Horz Seismic Coef.: 0.0875 TP-3 540 LB-2 Approximate location of Existing Building Elevation 490 440 390 340 290 240 190 0 100 200 300 400 500 600 700 Distance Cross Section A_Existing Condition 800 900 1,000 1,100 1,200