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为揭示高压水射流冲蚀作用下页岩破坏机制,以四川龙马溪组典型页岩为研究对象,开展淹没条件下水射流冲蚀破岩试验,采用扫描电子显微镜和计算机断层扫描(Computed Tomography,CT)图像三维重构技术,分析岩石宏观破坏过程和微观破坏形貌特征,并进行了砂岩对比试验.结果表明,在相同试验参数条件下,高压水射流冲蚀页岩破坏模式与砂岩有明显差别,页岩平均冲蚀速率和最大冲蚀深度均不到砂岩的1/2.力学机制分析认为,当高压水射流滞止压力小于页岩抗压强度时,在初始破碎坑形成阶段以拉伸破坏为主,出现岩块崩落现象;在射流成孔阶段,射流冲击力不断下降,难以产生拉张破坏或压剪破坏,此时以射流剥蚀矿物破坏为主.研究结果可为水射流提高页岩破碎效率提供理论指导.
In order to reveal the mechanism of shale failure under high pressure water jet erosion, taking the typical shale of Longmaxi Formation in Sichuan Province as the research object, the water jet erosion and rock breaking tests under submerged conditions were carried out. The scanning electron microscopy and computed tomography (CT) ) Images were used to analyze the macroscopic failure process and microstructure characteristics of the rocks, and sandstone comparison tests were carried out.The results show that under the same experimental parameters, the failure mode of high pressure water jet erosion shale is obviously different from sandstone , The average shale erosion rate and the maximum erosion depth are less than 1/2 of the sandstone.The mechanical mechanism analysis shows that when the stagnation pressure of high pressure water jet is less than the compressive strength of shale, Which is mainly caused by rock burst, and the impact of rock jet is decreasing, so it is hard to produce tensile failure or pressure-shear failure, which is dominated by the erosion of mineral by jet erosion. Rock crushing efficiency provides theoretical guidance.