Miami, FL: Cement-Bentonite Slurry Wall Installation, Phase 1 Seepage Barrier Levee L-31N Canal
This project was a larger pilot test, than its counterpart constructed in 2009, to reduce water loss from the everglades into the L-31 N canal. The limestone subgrade was allowing a considerable amount of water from the everglades to be lost into the L-31 canal. A cement-bentonite (CB) slurry wall was installed along the west side of the L-31 N canal at the toe of the levee, through a very porous limestone. Several wells were installed along the down gradient side of the trench to monitor groundwater flow. Based on piezometer and well readings, there was an immediate positive effect on the flow. To facilitate the digging process through the very hard limestone, the trench alignment was pre-excavated with a rock trenching machine. The trench was backfilled with excavated spoils, which allowed the CB slurry wall construction to proceed conventionally.
For the construction effort, Geo-Solutions provided turnkey construction of the CB wall. Key specialty equipment used on the project included GSI's custom long stick attachment to fit a Komatsu PC 400, fully automated batch plant and a bentonite slurry mix plant.
The CB slurry wall met the requirements of a 28-day strength (unconfined compressive strength) equal to or above 10 PSI and permeability in the 10-6 cm/sec range. The project was completed with zero incidents, on time and within budget.