Effect of Varying Shear Velocity on the Mechanical Behavior of Jointed Rock Subjected To Lower Normal Load

Abstract

: This study investigates the effect of shearing velocity on the mechanical behavior of rock joints, namely, the shear strength, residual strength, joint dilation, its surface roughness and the shearing stiffness under the application of lower normal load. The slower rate of shearing plays an important role in creep and the fatigue effect on jointed rock masses whereas, higher rate of shearing is experienced in the cases of dynamic loadings such as earthquake ground motion, blasting, drilling and traffic loading. In order to study the influence of shear velocity on the mechanical behavior of joints, CNL direct shear test are conducted at the geotechnical engineering laboratory of Kyoto University, Japan. The shear velocity effects the degree of interaction between the joint wall and the change in the surface roughness, which is brought upon by the asperity degradation during shearing. Finally, these phenomena will have the significant effect on the overall mechanical properties of the joint. However, under the lower normal load (< 1.00 MPa) shear velocity has no serious effect on the mechanical properties of the joint. Hence, based on the experimental results, its effect can be neglected for the normal confining stress less than 1.00 MPa. Eventually, the results of this work can help in studying the weak nature of jointed rock slopes under dynamic loading conditions which would be the main focus of this research work in near future.