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高压水射流冲击岩石会导致其发生结构破坏,不同的射流速度下,岩石呈现出各异的破坏形式。基于理论研究,分析水射流冲击岩石的应力波效应。选取速度分别为157,316,447,547,632,707和774 m/s的高压水射流开展冲击砂岩试验,分析不同射流速度下,砂岩内裂纹的数量、尺寸与形态。采用有限元法数值模拟了水射流破碎砂岩的过程,分析岩石内应力波的传播规律与裂纹的产生过程。研究表明:(1)当射流速度大于72 m/s时,砂岩表面出现破碎坑和环形裂纹,前者由水锤压力的剪切作用导致,后者由瑞利表面波的拉伸作用导致;(2)当射流速度为300~700 m/s时,砂岩内部产生大量的横向裂纹并出现体积破碎,裂纹的产生主要由应力波产生的径向拉伸应力导致;(3)当速度大于700 m/s时,砂岩产生的横向裂纹减少,主要以劈裂剪切方式破坏。
High-pressure water jet impact on the rock will lead to its structural damage, different jet velocity, the rock showing different forms of destruction. Based on the theoretical study, the stress wave effect of water jet impinging on rock is analyzed. High pressure water jets of speeds of 157, 316, 447, 547, 632, 707 and 774 m / s were selected to carry out impact sand tests to analyze the number, size and morphology of cracks in sandstone at different jet velocities. The finite element method was used to simulate the process of water jet breaking sandstone. The propagation law of stress waves and the crack initiation process were analyzed. The results show that: (1) When the jet velocity is more than 72 m / s, the surface of the sandstone is broken and the annular cracks appear. The former is caused by the shear effect of water hammer pressure and the latter is caused by the Rayleigh surface wave tension. 2) When the jet velocity is 300-700 m / s, a large number of transverse cracks are generated inside the sandstone and the volume is crushed. The crack is mainly caused by the radial tensile stress caused by the stress wave. (3) When the velocity is more than 700 m / s, the lateral cracks produced in the sandstone decrease and are mainly destroyed by splitting and shearing.