Experimental Investigation of the Permeability Measurement of Radial Flow through a Single Rough Fracture under Shearing Action

Abstract

Water flow is commonly observed in rock fractures, and this flow has considerable significance in many aspects of rock engineering. In this study, seepage-stress coupled tests were performed on fractured rock masses using a computer-controlled direct shear device for rock with seepage control. The flow direction was radial. Eight types of test case were designed, and subgroup tests with varied normal stress, shear velocity, and roughness of fracture surface were conducted. The failure state of the fracture surface after the shear test, changes in shear stress, and fissure width and permeability under the above conditions were analyzed. The results include the following: the grain size of gouge fragments produced in rough fracture decreased with an increase in normal stress during shearing; the grain size of gouge fragments affected the fracture permeability; and the influence of shear velocity on the test results was mainly reflected after the peak strength. Additionally, a new expression describing fluid flow through fracture gouge is proposed.

Study on Seepage Characteristics of Radial Flow in Rock Mass Based on Radius Effect

“…e effect of shear loads can lead to the relative displacement between the upper and lower fracture walls. e variation of interior geometries as the shear displacement increases is determined by many factors such as roughness, mechanical properties of the fracture surface, and infillings [10], and the hydraulic conductivity may exhibit multiple variations [8,[11][12][13]. Shear dilation of fractures is inhibited by the increase in normal stress due to the combined effect of normal and shear stresses, and the two factors have completely different effects on the variation of fracture aperture [14,15].…”