2025 01 14 West Essex Highlands Development Building D Slope Stability Study

Global Slope Stability Study for Building D West Essex Highlands Project Langan Project No.: 101049801 14 January 2025- Page 7 of 11 MEMO The rock encountered and cored during the investigation at the upper portion of the slope was classified as basalt. Rock properties were estimated using values recommended in the SLOPE/W manual and a Geologic Strength Index (GSI) of 65, an intact rock parameter (mi) of 17, a disturbance factor (D) of 1 and an unconfined compressive strength (UCS) of 316,800 psf (lowest laboratory value) were used in the analyses. Groundwater For our main analysis, groundwater was assumed to be at the top of the decomposed rock / very dense granular soil layer. It should be noted that our subsurface investigation was performed during a time of drought and not during the wet season. To account for groundwater fluctuation, a parametric sensitivity analysis was also performed to evaluate the impact of higher groundwater. Proposed Building D Loading Proposed Building D will be 4-stories above structured parking. A total uniform service load of 1,000 psf was applied to the eastern slope to simulate the effect of the proposed building. This service load estimate was derived from live loads specified in the New Jersey UCC Building Subcode 2021 and an approximate estimation of the dead loads. LEM Analyses and Results (Service Loads) The LEM analyses were performed to represent the pre-construction condition and postconstruction condition after the construction of the structure. We used the Morgenstern-Price LEM for our analysis, which satisfies the equilibrium of forces and moments. To consider the effect of the proposed construction on slope stability, the critical slip surfaces for the existing and proposed gravity (static) loading conditions for Sections A and B are provided in the tables below. LEM analysis results under gravity loading (static) conditions are presented in Appendix D. 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 = = =