目的目的为研究砂岩在多次高温-水冷却循环作用下的物理力学性能和损伤特征,方法方法对砂岩进行200~600℃下高温-水冷却循环试验。通过超声波纵波波速测试、物理参数测量、单轴压缩试验,分析高温-水冷却循环对砂岩物理力学性能的影响及损伤特征。结果结果结果表明:温度低于400℃时,砂岩试样质量损失较少,高于400℃时,质量损失较严重;随着温度升高和高温-水冷却循环次数增加,砂岩试样质量损失率增加,纵波波速降低;砂岩试样的弹性模量和峰值抗压强度在600℃时迅速下降,500~600℃时,存在影响砂岩试样弹性模量和峰值抗压强度的温度阈值;温度升高,砂岩试样损伤加剧,200℃时,随着高温-水冷却循环次数增加,砂岩试样强度提升,温度高于200℃时,随着循环次数增加,砂岩试样损伤加剧;砂岩试样单轴破坏模式以剪张复合破坏为主,随着循环次数增加,砂岩试样由斜向剪切破坏向锥形剪切破坏过渡,温度越高,砂岩试样锥形破坏块体越大。结论结论研究结果表明,高温-水冷却循环后,砂岩试样的物理力学性质严重劣化。

Objectives To study the physical and mechanical characteristics of sandstone under multiple high temperature-water cooling cycles, Methods the sandstone was subjected to high temperature-water cooling cycle tests at 200~600 ℃. The influence of these cycles on the physical and mechanical properties of sand‐stone samples was analyzed using ultrasonic longitudinal wave velocity test, physical parameter measure‐ments, and uniaxial compression tests. Results The results showed that the mass loss of sandstone samples was lower at temperatures below 400 ℃ , but became more significant at temperatures above 400 ℃ . As both the temperature and the number of high temperature-water cooling cycles increased, the mass loss rate of the sandstone samples increased, and the longitudinal wave velocity decreased. The elastic modulus and compressive strength of the samples decreased rapidly at 600 ℃ , with a temperature threshold affecting these properties between 500~600 ℃. At 200 ℃, the strength of the sandstone samples increased with the number of cycles, but when the temperature exceeded 200 °C, the damage increased with the number of cycles. The uniaxial failure mode of the sandstone samples was primarily shear-tension composite failure. With more cycles, the failure mode transferred to conical shear failure, and higher temperatures resulted in larger conical failure blocks. Conclusions The study indicated that the physical and mechanical properties of sandstone samples deteriorated significantly after high temperature-water cooling cycles.