Pelham, NY: Self-Hardening Slurry Wall, Pelham Former Mgp Site
Geo-Con was contracted to install a Self-Hardening Slurry (SHS) Wall, by the slurry trench method at a Former Manufactured Gas Plant Site (MGP) in Pelham, New York.
The wall will serve two purposes; as a temporary excavation support and hydraulic control structure for the eventual removal of contaminated soils at the site; as a permanent hydraulic control barrier to prevent the migration of any residual contamination from the site.
Geo-Con completed 1,060 linear feet of SHS Wall totaling 52,496 vertical square feet to an average depth of 49 feet below ground surface (bgs) with a maximum depth of 73 feet bgs. The wall was excavated using a Komatsu PC1250 LC8 excavator fitted with Geo-Con's custom made long-stick and boom. The SHS Wall was excavated in 20-foot panels to bedrock. Excavation was completed under slurry, which was left in place to harden and become the final backfill for the trench. The slurry was IMPERMIX®, a proprietary mixture of Granulated Blast Furnace Slag Cement and Attapulgite Clay. The IMPERMIX® attained an average 28-day strength of over 200 psi and a permeability of less than 1 x 10E-7 cm/s
The project was completed with zero health and safety related incidents.