Contaminated Soil Excavation & Disposal
Taplin was contracted by the Michigan Department of Natural Resources and Environment (DNRE) to excavate and dispose of gasoline-contaminated soil from a former auto center in Clinton Township, Michigan. The project required removal of several feet of overburden, and then installation of sheet piling walls to allow deep excavation and removal of contaminated soil.
Using a PC-300, the crew began by digging a five-foot deep trench around the perimeter of the project footprint in preparation for the installation of the sheet pile wall. The clean overburden was transported and stockpiled to an area located near the middle of the project footprint. Approximately 1,000 feet of sheet piling was installed by a sheeting subcontractor 34 feet below the trench floor and flush with the bottom of the trench. The piling was bolstered with additional support in the form of anchors and bracing installed at 25-foot intervals. The anchors consisted of a single sheet pile section driven 30 feet into the bottom of the excavation while the bracing involved a support beam installed between the sheet pile wall and the anchor. Crews then built a trench crossing to provide truck access.
Crews then installed a well-point dewatering system to control groundwater within the sheeted area. The crew began excavation of the impacted soil beginning at the northwest corner of the footprint. To ensure the stability of the sheet as the soil was removed, Taplin designed a special leapfrogging approach that also helped to make the excavation process more efficient. Taplin worked in 50-foot sections, first taking out 12 feet of overburden and stock piling to get at the contaminated soil below. The contaminated soil was then excavated to a depth of about 26 feet and then backfilled immediately using the stockpiled overburden. Since the soil was impacted with gasoline, Taplin utilized a vapor suppressant foam to minimize the risk of fire.More than 23,000 tons of contaminated soil were removed and transported to a designated landfill in Lenox, Michigan. The project lasted 15 weeks and was completed within budgetary parameters.