Experimental Study on Seepage and Stress of Single-fracture Radiation Flow

Abstract

Studying the stress distribution and water flow law of rocks under stress and seepage pressure in different directions can provide a certain basis for rock stability. In this experiment, a test system instrument for coupling direct shear and seepage of rock joints was developed to analyze the fracture seepage and shear stress of the relatively smooth surface formed by gypsum specimens. The seepage considered in this study refers to the groundwater at a depth of 80–150 m below the surface. Moreover, a radiation flow model was established, and a new law was obtained by fitting the relationship between flow rate and mechanical aperture. The shear process was divided into three phases. Normal stress and contact surface undulation had a considerable influence on shear stress. A two-dimensional numerical model showed that the vortices were the important cause of damage to the radiation flow. Increasing the seepage pressure increased the flow velocity between the fractures. The maximum flow velocity on one side of the same shear direction was larger than that on the other side.