Evaluation of shear velocity dependency of rock fractures by using repeated shear tests

摘要

Understanding the deformational behaviors of rock foundations subjected to seismic loads is an important issue to ensure the stability and safety of some important structures such as dam and nuclear power plant. The discontinuities existing in rock masses play an important role in the stability assessment of the rock foundations, therefore, the mechanical properties of discontinuities, especially their shear behavior need to be adequately estimated. The shear behavior of rock fractures is usually estimated through direct shear tests at relatively low shear velocities. When a rock mass is subjected to seismic loads, the shear velocities could vary in a wide range depending on the seismic strength. In this study, repeated shear tests on artificial rock fracture samples are conducted with shear velocities ranging from 0.5 mm/min to 50 mm/min to estimate the effects of surface roughness, shear velocity and shear history on the shear behavior of rock fractures.