Investigation of slip characteristics and contact area evolution of rough rock discontinuity under impact shear load

Abstract

This study investigated theshear slip behavior and contact area evolution of rough rock discontinuities with impact shear load. First, the dynamic impact shear numerical simulation of rock samples with real rough rock discontinuities was carried out. Subsequently, the variety rule of slip displacement and velocity of rock discontinuity with impact velocity, confining stress and joint roughness coefficient (JRC) was studied. The variation in contact area and shear stress of rock discontinuity during shear was assessed. Finally, the effect of frictional force on the slip displacement and velocity and the effect of contact area and frictional force on the shear stress distribution were analyzed. The results showed that the slip displacement, velocity and shear stress are rate dependent. The slip displacement and velocity increase as the impact velocity increases and decrease as the confining stress and JRC increase. The contact area and shear stress distribution range of rock discontinuities decrease slightly as the impact velocity increases but increase significantly as the confining stress and JRC increase. The shear stress distribution range of rock discontinuities closely correlates with the contact area. The shear stress in the non‐contact area is zero. The shear stress distribution range increases as the contact area increases. The average shear stress increases as the frictional force increases. Moreover, the slip displacement and velocity of rock discontinuities decrease linearly as the frictional force increases.