Subsurface investigations revealed that significant seepage was evident through the underlying soils beneath the Lake Cherokee Spillway Dam, built in the 1940’s.
Originally designed as a soil-bentonite hydraulic barrier wall to retain the lake water, Geo-Solutions was able to design and construct a slag-cement-bentonite hydraulic barrier wall within the same budget. This improved wall would obtain equal permeability but barrier wall strengths would be many orders of magnitude better than the existing soils. The slag component in the wall resulted in barrier wall strengths that continue to get better over time.
Description of Work:
A Geo-Solutions’ custom modified batch plant in very confined space near the spillway allowed wall construction with lake water and dry reagents delivered to the site near the road entrance. A CAT 390 excavator provided sufficient power with an integral Geo-Solutions custom boom and stick, excavated the wall to a depth a 43 feet through difficult soils inter-bedded with iron-ore residuals. The length of the constructed wall was 32,240 vsf. The wall attained an unconfined compressive strength over 50 pounds per square inch and permeability exceeding one times ten to the minus seven centimeters per second. The wall was constructed to allow at least half of the spillway to function in the event of high lake or flood conditions.