(1. School of Resources，Environment and Safety Engineering，Hunan University of Science and Technology，Xiangtan，Hunan 411201，China；2. The SAWS Laboratory of Prevention and Controlling the Roof，Coal and Gas Outburst in Coal Mine of South China，Hunan University of Science and Technology，Xiangtan，Hunan 411201，China；3. Hunan Province Key Laboratory of Safe Mining Techniques of Coal Mines，Hunan University of Science and Technology，Xiangtan，Hunan 411201，China；4. State Key Laboratory of Coal Mine Disaster Dynamics and Control，Chongqing University，Chongqing 400044，China)
Abstract：The impingement of rocks by the high-velocity water jet causes the erosion of structures. The failure patterns of rocks subjected to water jet with different velocities vary greatly. The stress wave effect of water jet impacting on rock was analyzed based on the previous studies. A number of impacting experiments were conducted with the water jet velocities of 157，316，447，547，632，707 and 774 m/s respectively. According to the failure phenomenon of sandstone，the number，size and patterns of cracks inside the rock subjected to the water jet with different velocities were analyzed. Finite element models of water jet impacting on the cylindrical sandstone were established. The propagation of stress wave and the generation of cracks in rock were studied. The broken pit and the circumferential cracks on the surface of sandstone occurred when the velocity of water jet was above about 72 m/s，and the former was produced by the shear stress of water hammer pressure and the later was induced by the tensile component of Rayleigh wave. Many transverse cracks were produced by the radial tensile stress waves when the velocity was between 300 and 700 m/s. The major failure pattern of sandstone is the split cracks when the velocity is above 700 m/s.
2016, Vol. 35 
