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

MEMO Global Slope Stability Study for Building D West Essex Highlands Project Langan Project No.: 101049801 14 January 2025- Page 3 of 11 Langan. The borings and test pits were performed at accessible areas along two cross-sections running in the east-west direction through the subject area. The locations of the borings and test pits are shown on Figure 1. Logs of the borings and test pits are provided in Appendix A and Appendix B, respectively. Borings Four (4) borings, identified as LB-1 through LB-4, were drilled within the subject area by Craig Geotechnical Drilling Co. Inc. (Craig). The borings were performed using a track-mounted drill rig and mud-rotary drilling techniques. Borings extended approximately 19 ft to 50 ft below existing surface grades. Borings LB-1 and LB-3 were performed at the higher portion of the slope near the proposed Building D footprint area. Borings LB-2 and LB-4 were performed east of the existing sewer easement located at the lower portion of the slope. Soil samples were collected, and Standard Penetration Tests (SPT) were performed using a standard 2-inch outside-diameter split-spoon sampler driven by a 140-pound automatic hammer in accordance with ASTM D1586. Soil sampling and SPTs were typically performed continuously in the upper 12 ft and at 5 ft intervals thereafter. Recovered soil samples were visually examined and classified in the field in accordance with the Unified Soil Classification System (USCS). Where encountered, rock was cored for a minimum of 10 ft using an NQ-sized core barrel. Test Pits Eight (8) test pits were excavated by Frank Semeraro Construction using a John Deere 75G excavator. Test pits identified as TP-1 through TP-8 were performed throughout the subject area and extended approximately 3.5 ft to 13 ft below existing surface grades. Upon completion, the test pits were backfilled with excavated materials and the backfill was compacted with the excavator bucket. Geotechnical Laboratory Testing Soil and rock samples collected during the subsurface investigation were classified and examined in the field by a Langan geotechnical engineer. Representative rock samples were tested by a geotechnical laboratory to determine the unconfined compressive strength of the rock. The results of the laboratory tests are included in Appendix C. SUBSURFACE CONDITIONS The generalized subsurface conditions consisted of

y to determine the unconfined compressive strength of the rock. The results of the laboratory tests are included in Appendix C. SUBSURFACE CONDITIONS The generalized subsurface conditions consisted of surficial materials (topsoil) underlain by natural sand and silt overlying a decomposed rock and rock strata. Detailed descriptions of the subsurface conditions are given below. Surficial Materials = = =