2025 06 18 WEH Slope Stability Analysis Letter Report

Global Slope Stability Study for Building D West Essex Highlands Project Langan Project No.: 101049801 Revised 18 June 2025 Revised 18 June 2025 - Page 9 of 13 MEMO the existing and proposed gravity (static) loading conditions for Sections A, B, C and D are provided in the tables below. LEM analysis results under gravity loading (static) condition satisfy a minimum acceptable factor of safety of 1.5, and are presented in Appendix E. Table 2A - LEM Factors of Safety against Sliding for Service Loads – Section A Condition Critical Slip Surface Critical Slip Surface That Reaches the Downslope Building Existing 2.20 3.29 Proposed 2.20 3.29 Table 2B - LEM Factors of Safety against Sliding for Service Loads – Section B Condition Critical Slip Surface Critical Slip Surface That Reaches the Downslope Building Existing 1.67 6.46 Proposed 1.67 6.45 Table 2C - LEM Factors of Safety against Sliding for Service Loads – Section C Condition Critical Slip Surface To Upper Tier Retaining Wall Existing 1.59 Proposed 1.59 Table 2D - LEM Factors of Safety against Sliding for Service Loads – Section D Condition Critical Slip Surface within Site Limits Existing 1.94 Proposed 1.94 Seismic Slope Stability Analyses Seismic slope stability analyses have traditionally been performed by using pseudo-static limit equilibrium analyses. These analyses consist of applying a lateral force to the slope equal to the product of a seismic coefficient (kh) and the weight of the slope. The seismic coefficient is based on the actual anticipated level of acceleration in the failure mass and corresponds to some