The Job
CJGeo was called to perform emergency safety repairs at the historic Silver Lake Dam in Harrisonburg, Virginia. The project focused on mitigating persistent seepage and soil loss through the earthen dam embankment. The owner required a method to restore the safety of the dam while preserving its historical appearance.
Silver Lake Dam Polyurethane Grouting Before and After
The Challenge
Persistent seepage flowed through the 12-foot tall embankment. This constant water loss prevented the lake from maintaining its normal pool level. Flowing water also caused internal erosion, creating dangerous sinkholes at the surface and compromising the dam. A previous repair attempt involved the installation of a 7-foot-deep concrete cut-off trench to control seepage. This eventually failed as the water found a new path around the rigid barrier.
Site access and preservation presented significant constraints, and preserving the historic landmark was a top priority for the owner. As such, the owner prioritized finding a solution that would restore safety to the dam while limiting surface disturbance.
The Solution
CJGeo proposed installing a polyurethane grout curtain to cut off the water flow. Crews injected CJGrout along approximately 50 linear feet of the dam. The injection followed a grid pattern to the full 12-foot depth along the existing earthen embankment, which experienced seepage. This process cut off the seepage pathways that bypassed the old concrete trench, forcing the water to flow through the fall as intended and restoring the pool to its normal levels.
The expanding polyurethane also filled voids created by years of soil erosion. This re-stabilized the embankment and mitigated the risk of future sinkhole formation, ensuring long-term dam safety. The team completed the entire repair without using excavators or disturbing the surface.
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