In this paper, the characteristics of microscopic failure and macroscopic mechanics of gritstone are studied experimentally under geothermal conditions. Different hydrothermal and cooling treatments are conducted to simulate geothermal environments. Permeability and triaxial compression tests of treated gritstone specimens are employed to obtain complete stress–strain curves and permeability and to discuss the mechanical properties of gritstone under various high-temperature, high-pressure, and cooling conditions. The results show that, in the hydrothermal study, the triaxial compressive strength of gritstone increases as the pre-treating pressure. In the cooling study, the specimen cooled in an autoclave had the lowest strength and the largest peak strain, while the air-cooled specimen had the greatest strength. Furthermore, pre-treatment with water at high pressure and temperature had a significant influence on the permeability of specimens. The permeability increased with increasing pre-treatment water pressure. In the cooling study, specimens cooled in an autoclave had the highest permeability. The microscopic characteristics of gritstone were analyzed by scanning electron microscopy (SEM) images. The SEM images showed that internal defects, such as microcracks induced by hydrothermal and cooling treatments, led to differences in macroscopic behavior. X-ray electron diffraction (XRD) data reflected the changes in the composition and content of specific minerals before and after treatment, and these changes were related to hydrothermal coupling. Analysis of the micro and macro characteristics showed that the temperature and pressure in the geothermal environment affected cracking and dissolution in gritstone, stimulating the initiation and propagation of cracks.

本文对地热条件下砂砾岩的微观破坏特征和宏观力学进行了实验研究。进行不同的水热和冷却处理来模拟地热环境。通过对处理过的砂砾岩试样进行渗透率和三轴压缩试验，获得完整的应力-应变曲线和渗透率，并讨论了砂砾岩在各种高温、高压和冷却条件下的力学性能。结果表明，在热液研究中，砂砾岩的三轴抗压强度随着预处理压力的增加而增加。在冷却研究中，在高压釜中冷却的试样具有最低的强度和最大的峰值应变，而风冷的试样具有最大的强度。此外，在高压和高温下用水预处理对样品的渗透性有显着影响。渗透率随着预处理水压的增加而增加。在冷却研究中，在高压釜中冷却的样品具有最高的渗透性。通过扫描电子显微镜 (SEM) 图像分析了砂砾岩的微观特征。SEM 图像显示内部缺陷，例如由水热和冷却处理引起的微裂纹，导致宏观行为的差异。X射线电子衍射（XRD）数据反映了处理前后特定矿物的组成和含量的变化，这些变化与水热耦合有关。