The development of deep geothermal resources encounters challenges related to high temperatures and hard reservoir rocks. Abrasive water jets (AWJ) offer a potential solution to enhance the efficiency of breaking high-temperature hard rocks in deep ground. This mainly originated from their combined characteristics of jet cooling impact and high-speed abrasive grinding. In order to investigate the dynamic deformation process and rock-breaking mechanism of high-temperature hard rocks cut by AWJ, laboratory tests were conducted on high-pressure abrasive water jets cutting granite, sandstone, and marble. Rock strains were monitored using dynamic strain gauges and the digital image correlation (DIC) technique. The results indicate that in the process of abrasive jet cutting high-temperature hard rock, the rock strain is divided into three stages: compression deformation, deformation release, and stable deformation. The strain response zone can be divided into strain concentration zone, strain transition zone, and strain weak response zone. The high strain region and heat exchange region of high-temperature hard rock during AWJ cutting process are almost consistent. Jet vaporization weakens the water cushion effect during the water hammer stage, leading to high strain concentration at the stagnation point of the jet. During the stagnation stage, the fluid weakens the binding of particles, the abrasive becomes more divergent, and the range of high strain response region expands. Unlike the dynamic strain generated by jet erosion of hard rock, when jet cutting rocks, the strain in the vertical jet direction is generally greater than that along the jet direction. The cutting effect increases with the increase of rock temperature. When the rock temperature is 300 °C, the cutting depth of sandstone, granite, and marble increases by 50 %, 120 %, and 180 %, respectively. Under the combined effects of high-frequency jet impact, high-speed abrasive grinding, and thermal stress, hard rock undergoes varying degrees of damage and failure.

中文翻译：

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磨料水射流切割高温硬岩动态变形及破碎机理实验研究


深层地热资源开发面临高温、储层岩石坚硬等挑战。磨料水射流 (AWJ) 提供了一种潜在的解决方案，可以提高破碎深层地下高温硬岩的效率。这主要源于它们喷射冷却冲击和高速磨料磨削的综合特性。为研究AWJ切割高温硬岩的动态变形过程和破岩机理，开展了高压磨料水射流切割花岗岩、砂岩、大理石的室内试验。使用动态应变仪和数字图像相关（DIC）技术监测岩石应变。结果表明，磨料射流切割高温硬岩过程中，岩石应变分为压缩变形、变形释放和稳定变形3个阶段。应变响应区可分为应变集中区、应变过渡区和应变弱响应区。 AWJ切削过程中高温硬岩的高应变区和热交换区几乎一致。射流汽化削弱了水锤阶段的水垫效应，导致射流驻点处应变集中。在停滞阶段，流体削弱了颗粒的结合，磨料变得更加发散，高应变响应区域的范围扩大。与硬质岩石射流侵蚀产生的动应变不同，射流切割岩石时，垂直射流方向的应变一般大于沿射流方向的应变。切削效果随着岩石温度的升高而增强。 当岩石温度为300℃时，砂岩、花岗岩和大理石的切削深度分别增加50%、120%和180%。在高频射流冲击、高速磨料研磨和热应力的综合作用下，硬岩发生不同程度的损伤和破坏。