Bogalusa, LA: Groundwater Barriers and Collection Trench, Temple Inland
The purpose for the construction of the groundwater barrier and the collection trench was to limit possible lime intrusion into the Bogalusa Creek from a non-operational underground landfill used by the paper mill about 50 years ago, and to remove and treat groundwater. For groundwater collection, a bio-polymer trench was installed. To prevent lime intrusion into the creek, a soil-bentonite slurry wall was installed. Several areas of jet grouted barrier wall were also constructed due to the presence of utilities.
Geo-Solutions, Inc. worked as the primary subcontractor to ARCADIS. GSI was responsible for turnkey construction of the groundwater barriers and collection trench. GSI crews installed a 2,310 linear foot biopolymer collection trench. The trench was excavated to a depth of 20 feet under a biopolymer slurry. The slurry supported trench was then backfilled with a geotextile, 6" diameter collection pipe, and risers for future well installation. After trenching and backfilling were completed, the biopolymer slurry was degraded and the trench was developed by pumping and circulating of groundwater.
The slurry wall was 1,950 linear feet and was installed to a depth of 42 feet below ground surface. The trench was excavated with a Komatsu PC800 that was equipped with GSI's extended stick and slurry trenching bucket. The trench was excavated under a bentonite slurry and was backfilled with a low permeable soil bentonite backfill material. This provided groundwater cutoff from the plant area to the creek.
Due to both overhead and underground utilities, several sections of the cutoff wall could not be installed using slurry trench excavation techniques. In these sections, the groundwater cutoff wall was completed with jet grouting. Using GSI's jet pump and automated batch plant, columns up to 6 feet in diameter were created. The columns extended to a depth of 42 feet below ground surface.