- Construction Date: April 2019 to June 2019
- Location: Concord, NH
- Category: Soil Remediation
- State Street Soil Remediation :
In Spring 2019 NSI constructed 2 adjacent cofferdams for the deep excavation of contaminated soils at a former gasoline station. The extensive contamination and the instability of the silty clay soils required a pair of sequential 32 foot deep excavations. In the design 45’ sheets were installed along with multiple level of bracing and hydraulic megabraces.
In the end nearly 10,000 cu yds of contaminated soil were excavated and delivered to a thermal treatment site.