Experimental study of cohesive sediment consolidation and its effect on seepage from dam foundations

Cohesive sediment consolidation causes remarkable changes in the stress field and seepage field of dams and reservoirs, due to variations in the dry density of sediments. This study analyzed the physico-chemical characteristics of cohesive sediments, and the consolidation mechanism to develop a dynamic model and status formula for the density during the initial stage of consolidation. Flume experiments were then conducted using cohesive and non-cohesive sediment samples to verify the derived formula by comparing the calculated values to measured sediment pressures. Additionally, the effect of sediment consolidation on seepage from a dam foundation was investigated using ABAQUS software. This case study showed that the dry density of the sediment increased dramatically during the initial stage of consolidation (approximately 65% of the total growth), but it increased slowly in the later stage of the long process. The water head of the upstream anti-seepage wall was substantially weakened due to the natural blanket behind the dam.