2025 06 18 WEH Slope Stability Analysis Letter Report

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 2.204 640 TP-1 Critical Failure Failure surface Surface (CFS) TP-8 LB-1 TP-2 590 Factor of Safety: 2.204 Current Slip Surface Number: 327 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 2.201 640 Critical Critical Failure Failure Surfacesurface (CFS) TP-8 LB-1 8.2753 ft TP-1 TP-2 590 Factor of Safety: 2.201 Current Slip Surface Number: 327 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 3.293 640 TP-1 Criticalsurface Failure Failure Surface (CFS) TP-8 LB-1 TP-2 590 Factor of Safety: 3.293 Current Slip Surface Number: 221 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 3.285 640 Criticalsurface Failure Failure Surface (CFS) TP-8 LB-1 8.2753 ft TP-1 TP-2 590 Factor of Safety: 3.285 Current Slip Surface Number: 221 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

Cross Section B (Static Condition)

Color 690 Name Unit Weight (pcf) Effective Cohesion (psf) Effective Friction Angle (°) Bedrock 180 Decomposed Rock/Very Dense Granular Soil 135 0 38 Dense Dense to to Very Very Dens DenseSand Sand 125 0 34 Medium sand 120 0 32 Top soil 115 0 30 UCS Intact (psf) Intact Rock Geological Parameter Strength mi Index GSI Disturbance Factor D Piezometric Surface 323,263 17 1 1 65 1 1.669 640 Factor of Safety: 1.669 Current Slip Surface Number: 271 TP-7 TP-4 LB-3 B-13 TP-14 590 TP-5 Approximate Projected Location of Existing Building LB-4 540 TP-6 Elevation 490 Critical surface Failure Failure Surface (CFS) 440 390 340 290 240 190 0 100 200 300 400 500 600 700 Distance Cross Section B_Existing Condition 800 900 1,000 1,100 1,200

Color Proposed Building D.2 Name Unit Weight (pcf) Effective Cohesion (psf) Effective Friction Angle (°) Bedrock 180 Decomposed Rock/Very Dense Granular Soil 135 0 38 Dense to Dense to Very Very Dens Sand Dense Sand 125 0 34 Medium sand 120 0 Top soil 115 0 UCS Intact (psf) Intact Rock Parameter mi Geological Strength Index GSI Disturbance Factor D Piezometric Surface 323,263 17 65 1 1 1 32 Failure surface 30 690 1.676 640 TP-4 TP-14 Factor of Safety: 1.676 Current Slip Surface Number: 271 TP-7 LB-3 12 ft LB-13 590 TP-5 Approximate Projected Location of Existing Building LB-4 540 TP-6 Elevation 490 Critical surface Failure Failure Surface (CFS) 440 390 340 290 240 190 0 100 200 300 400 500 600 700 Distance Cross Section B_Proposed Condition 800 900 1,000 1,100 1,200

Color 690 Name Unit Weight (pcf) Effective Cohesion (psf) Effective Friction Angle (°) Bedrock 180 Decomposed Rock/Very Dense Granular Soil 135 0 38 Dense Dense to to Very Very Dens DenseSand Sand 125 0 34 Medium sand 120 0 32 Top soil 115 0 30 UCS Intact (psf) Intact Rock Geological Parameter Strength mi Index GSI Disturbance Factor D Piezometric Surface 323,263 17 1 1 65 1 6.467 640 Criticalsurface Failure Failure Surface (CFS) TP-7 TP-4 LB-3 B-13 Factor of Safety: 6.467 Current Slip Surface Number: 217 TP-14 590 TP-5 Approximate Projected Location of Existing Building LB-4 540 TP-6 Elevation 490 440 390 340 290 240 190 0 100 200 300 400 500 600 700 Distance Cross Section B_Existing Condition 800 900 1,000 1,100 1,200

Color Proposed Building D.2 Name Unit Weight (pcf) Effective Cohesion (psf) Effective Friction Angle (°) Bedrock 180 Decomposed Rock/Very Dense Granular Soil 135 0 38 Dense Dense to to Very Very Dens DenseSand Sand 125 0 34 Medium sand 120 0 32 Top soil 115 0 30 UCS Intact (psf) Intact Rock Parameter mi Geological Strength Index GSI Disturbance Factor D Piezometric Surface 323,263 17 65 1 1 1 690 6.448 640 TP-4 TP-14 Factor of Safety: 6.448 Current Slip Surface Number: 217 Critical surface Failure Failure Surface (CFS) TP-7 LB-3 12 ft LB-13 590 TP-5 Approximate Projected Location of Existing Building LB-4 540 TP-6 Elevation 490 440 390 340 290 240 190 0 100 200 300 400 500 600 700 Distance Cross Section B_Proposed Condition 800 900 1,000 1,100 1,200

Cross Section C (Static Condition)