Soil-Cement-Bentonite (SCB) wall installation Update

Four Lakes Task Force has engaged a specialty contractor to install a soil-cement-bentonite (SCB) wall as a cutoff wall through the center of the existing earthen embankment at Edenville Dam.

The SCB wall is constructed using a trencher. The trencher utilizes existing soil from the embankment and adds cement and bentonite (clay) which hardens over time to form a very low permeable wall that reduces water flow through the embankment when the lake returns.
 
The SCB wall ranges from 40 to 90 feet deep as it trenches into the native glacial till, which exists below the embankment. This is a more cost-effective practice for longer length cutoff walls as opposed to driving steel sheet pile. The work began on August 22nd approximately 100 feet from the powerhouse and is progressing west towards M-30. They have progressed approximately 2,200 feet since starting and are making excellent progress.

During this construction, the team kept a close eye on the dam’s response to the installation. Changes in water pressure within the embankment and minor lateral movement or deflections were measured using vibrating wire piezometers and inclinometers to maintain safe operations and integrity of the embankment.