Experimental Study on Permeability of Fractured Sandstone with Different Tips

According to the seepage characteristics of fractured rock mass of hydropower slope insouthwest mountainous area,and taking the sandstone at left bank slope of Jinping HydropowerStation as an example, this paper tests and studies the permeability characteristics of rocksamples prefabricated with artificial fracture in different tips under different confining pressuresand osmotic pressures by high pressure rock permeameter, and statistically analyzes thepermeability coefficients obtained from the tests. The test results show that with the increase ofosmotic pressure from 0.1 MPa to 0.5 MPa, the dissolution and scouring of hydrophilic minerals infractured sandstone increase gradually, resulting in new seepage channels and the increase ofpermeability coefficient. With the increase of confining pressure from 2 MPa to 4 MPa, thefracture and pore in the rock are closed by compression, leading to the reduction of permeabilitycoefficient. The overall permeability coefficient of fractured sandstone with tips of 0°, 30° and45°decreases in turn, and the increase of fracture dip changes the angle between fracture seepagechannel, initial seepage direction and confining pressure, which weakens the response ofpermeability coefficient to confining pressure and osmotic pressure.