Li Chun, Feng Gan, Zhang Xinran, Zhang Chunwang, Hu Yaoqing, Meng Tao
School of Mining Engineering, Taiyuan University of Technology, Taiyuan, 030024, Shanxi, China.
State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource & Hydropower, Sichuan University, Chengdu, 610065, China.
Sci Rep. 2024 Jul 7;14(1):15630. doi: 10.1038/s41598-024-66073-2.
In the geothermal development of hot dry rock (HDR), both the drilling of the wellbore and the heat exchange of the heat reservoir involve the effects of different cold and hot conditions on the high-temperature rock mass. The testing machine for rock mechanics was used to conduct a uniaxial compression test and carry out micro testing on the treated samples; furthermore, with the help of scanning electron microscopy the fracture mechanism of granite subjected to different temperatures and cooling methods was studied. The results show: (1) With the gradual increase in temperature, the compressive strength of granite under the two cooling methods gradually decreases. (2) The failure modes of the samples under the two cooling methods are mainly shear failure of the "Y" type. The degree of damage of the sample under water cooling is significantly greater than that under natural cooling. Electron micrographs could confirm these results. (3) It can be obtained by testing the mineral composition and element changes of granite at different temperatures. When the temperature reaches 600℃, its change is more pronounced. The results of this study can provide a theoretical reference for the failure of the wellbore and the degree of fracture of the thermal reservoir rock mass during geothermal development.
在干热岩（HDR）地热开发中，井筒钻进和热储热交换均涉及不同冷热条件对高温岩体的影响。利用岩石力学试验机对处理后的样品进行单轴压缩试验并开展微观测试；此外，借助扫描电子显微镜研究了不同温度及冷却方式作用下花岗岩的断裂机理。结果表明：（1）随着温度逐渐升高，两种冷却方式下花岗岩的抗压强度均逐渐降低。（2）两种冷却方式下样品的破坏模式主要为“Y”型剪切破坏。水冷作用下样品的损伤程度明显大于自然冷却。电子显微镜照片可证实这些结果。（3）通过测试不同温度下花岗岩的矿物成分及元素变化可得，当温度达到600℃时，其变化更为显著。本研究结果可为地热开发过程中井筒破坏及热储岩体破裂程度提供理论参考。
