Experimental Study on the Slip Characteristics of Jointed Rock Masses with Different Dip Angles Under Impact Loading

The strong interaction between impact loading and joints can induce slip instability in jointed rock masses, posing a serious threat to construction safety and long-term stability in rock engineering. To investigate the dynamic slip characteristics of rock-like specimens containing an artificial persistent joint under impact loading, cement mortar rock like specimens with joint dip angles of 50°, 60°, and 70° were prepared. Impact tests were conducted using an SHPB system combined with high-speed imaging and DIC. The results show that the presence of joints significantly deteriorates the dynamic load-bearing capacity of the rock mass and reduces stress-wave transmission. As the joint dip angle increases from 50° to 70°, the shear stress component acting on the joint decreases, while the normal constraint increases. As a result, joint slip is suppressed, and both slip displacement and slip velocity decrease. Joint slip can induce secondary cracks to propagate into the rock matrix, but failure becomes more localized along the joint as the dip angle increases. Increasing impact loading intensity significantly increases the dynamic strength of jointed rock masses, intensifies joint slip, and induces more severe secondary damage. Energy analysis shows that joints change the energy dissipation mechanism. The input energy is mainly dissipated through joint compression deformation, shear slip, and induced secondary damage. The results provide a reference for stability evaluation and dynamic disaster prevention in jointed rock masses under impact disturbance.