(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.
[1] MOMBER A W. An SEM-study of high-speed hydrodynamic erosion of cementitious composites[J]. Composites Part B-Engineering，2003，34(2)：135–142.
[2] 李晓红，卢义玉，赵 瑜，等. 高压脉冲水射流提高松软煤层透气性的研究[J]. 煤炭学报，2008，33(12)：1 386–1 390.(LI Xiaohong，LU Yiyu，ZHAO Yu，et al. Study on improving the permeability of soft coal seam with high pressure pulsed water jet[J]. Journal of China Coal Society，2008，33(12)：1 386–1 390.(in Chinese))
[3] 李晓红，杨晓峰，卢义玉，等. 水射流辅助硬质合金钻头切割岩石过程的刀具温度分析[J]. 煤炭学报，2010，35(5)：844–849.(LI Xiaohong，YANG Xiaofeng，LU Yiyu，et al. Temperature analysis of cemented carbide drill cutting rock associated with water jet[J]. Journal of China Coal Society，2010，35(5)：844–849.(in Chinese))
[4] BOWDEN F P，BRUNTON J H. Damage to solids by liquid impact at supersonic speeds[J]. Nature，1958，181：873–875.
[5] BOWDEN F P，FIELD J E. The Brittle Fracture of Solids by Liquid Impact，by Solid Impact，and by Shock[J]. Proceedings of the Royal Society A，1964，282：331–352.
[6] MOMBER A W. Deformation and fracture of rocks due to high-speed liquid impingement[J]. International Journal of Fracture，2004，130(3)：683–704.
[7] 黄 飞，卢义玉，刘小川，等. 高压水射流冲击作用下横观各向同性岩石破碎机制[J]. 岩石力学与工程学报，2014，33(7)：1 329– 1 335.(HUANG Fei，LU Yiyu，LIU Xiaochuan，et al. Breakage mechanism of transverse isotropic rock subjected to high-pressure water jet[J]. Chinese Journal of Rock Mechanics and Engineering，2014，33(7)：1 329–1 335.(in Chinese))
[8] 卢义玉，张 赛，刘 勇，等. 脉冲水射流破岩过程中的应力波效应分析[J]. 重庆大学学报，2012，35(1)：117–124.(LU Yiyu，ZHANG Sai，LIU Yong，et al. Analysis on stress wave effect during the process of rock breaking by pulsed jet[J]. Journal of Chongqing University，2012，35(1)：117–124.(in Chinese))
[9] 卢义玉，黄 飞，王景环，等. 超高压水射流破岩过程中的应力波效应分析[J]. 中国矿业大学学报，2013，42(4)：1–7.(LU Yiyu，HUANG Fei，WANG Jinghuan，et al. Analysis on the stress wave effect during the process of rock breakage by ultrahigh pressure water jet[J]. Journal of China University of Mining and Technology，2013，42(4)：1–7.(in Chinese))
[10] FIELD J E. ELSI conference：invited lecture：liquid impact：theory，experiment，applications[J]. Wear，1999，233–235：1–12.
[11] MOMBER A W. Synergetic effects of secondary liquid drop impact and solid particle impact during hydro-abrasive erosion of brittle materials[J]. Wear，2004，256(11–12)：1 190–1 195.
[12] 李根生，廖华林. 超高压水射流冲蚀切割岩石断口微观断裂机制试验研究[J]. 高压物理学报，2005，19(4)：337–342.(LI Gensheng，LIAO Hualin. Micro-failure mechanism analysis and test study for rock failure surface under water jet impact[J]. Chinese Journal of High Pressure Physics，2005，19(4)：337–342.(in Chinese))
[13] 倪红坚，王瑞和，葛洪魁. 高压水射流破岩的数值模拟分析[J]. 岩石力学与工程学报，2004，23(4)：550–554.(NI Hongjian，WANG Ruihe，GE Hongkui. Numerical simulation on rock breaking under high pressure water jet[J]. Chinese Journal of Rock Mechanics and Engineering，2004，23(4)：550–554.(in Chinese))
[14] OBARA T，BOURNE N K，FIELD J E. Liquid-jet impact on liquid and solid surfaces[J]. Wear，1995，186–187：388–394.
[15] FIELD J E. Liquid impact：theory，experiment，applications[J]. Wear，1999，233–235：1–12.
[16] COOK S S. Erosion by Water-Hammer[J]. Proceedings of the Royal Society A，1928，119：481–488.
[17] MOMBER A W. Energy transfer during the mixing of air and solid particles into a high-speed water jet：an impact-force study[J]. Experimental Thermal and Fluid Science，2001，25(1)：31–41.
[18] HOLMQUIST T J，JOHNSON G R. A computational constitutive model for glass subjected to large strains，high strain rates and high pressures[J]. Journal of Applied Mechanics，2011，78(5)：051003.
[19] 李根生，廖华林，黄中伟，等. 超高压水射流作用下岩石损伤破碎机制[J]. 机械工程学报，2009，45(10)：284–293.(LI Gensheng，LIAO Hualin，HUANG Zhongwei，et al. Rock damage mechanisms under ultra-high pressure water jet impact[J]. Journal of Mechanical Engineering，2009，45(10)：284–293.(in Chinese))
2016, Vol. 35 
