The Experimental Research on the Effect of Seepage Pressures on Seepage Time through Red Sandstone

Abstract

The cyclic fluctuation of reservoir water level makes soft rock in bank slope under cyclic seepage pressure and will bring certain effects on permeability characteristics of the soft rock. In order to obtain the relationship between the seepage pressure and seepage time, permeability tests were conducted on red sandstone specimens (from Three Gorges Reservoir Area, China) under cyclic seepage pressures by the self-developed equipment with the function to simulate cyclic fluctuation of reservoir water level. Experimental results show that the water infiltration of the sample was not stable in first three cycles, and it changed from 0.444 mL to 0.086mL. After three cycles, the water infiltration fluctuated between 0.060mL and 0.069mL. It can be drawn that the seepage velocity increase with the raise of pressure and it fit a four times polynomial in each cycle. The study indicates that increasing the seepage pressure appropriately can improve the seepage velocity, and greatly shorten the seepage time.