Epigenetic Gorges and Their Treatments for Dam Safety: Case from Kundghat Dam, District Jamui, Bihar, India

A major engineering challenge was encountered during the construction of the Kundghat Dam in Bihar, India. During excavation for the dam’s foundation, a buried river channel (paleo-channel) was discovered. The paleo-channel, or epigenetic gorge, was a deeply eroded trench in the bedrock filled with highly permeable materials and proved to be a significant geological surprise. This geological feature posed two major threats: first, potential leakage due to the porous nature of the paleo-channel material, and second, settlement within such deposits. To ensure the dam’s long-term safety, a series of grouting techniques was implemented to reduce the permeability of the paleo-channel material. The remedial measures included row grouting, grout curtains, and Tube-à-Manchette (TAM) grouting, a specialized method that allows multiple, controlled injections into the same area to achieve thorough material consolidation. The use of these advanced grouting methods successfully stabilized the dam’s foundation, mitigated the risks associated with the paleo-channel, and ensured the structural integrity of the Kundghat Dam.