During drilling, reservoir fracturing and hot dry rock development, high-temperature rock is subjected to cyclic water cooling. The mechanical properties and microscopic characteristics of granite exposed to high-temperature and water-cooling cycles were investigated experimentally. The results show that the uniaxial compressive strength and elasticity modulus decrease with increasing temperature and cycles, especially above 400 °C and after 1 cycle. In addition, the P-wave velocity decreases continuously and rapidly with temperature and it drops dramatically after 1 cycle and then more slowly with increasing cycles. The inhomogeneous expansion of minerals and cyclic thermal shock are the essential reasons for rock deterioration. The decay of elasticity modulus and enlargement of void space stops the damage to granite from being aggravated after a certain number of cycles. There is a good correlation between the P-wave velocity and mechanical parameters, and the damage factor based on the uniaxial compressive strength and elastic modulus has a positive correlation with the damage factor obtained by the ultrasonic method, illustrating that the ultrasonic method can be utilized to reflect the changes in mechanical characteristics.

在钻探，储层压裂和干岩热发展过程中，高温岩石要经过循环水冷却。实验研究了暴露于高温和水冷循环的花岗岩的力学性能和微观特性。结果表明，单轴抗压强度和弹性模量随温度和循环次数的增加而降低，尤其是在400°C以上和1个循环后。另外，纵波速度随温度连续而迅速地下降，在1个周期后急剧下降，然后随着周期的增加而下降得更慢。矿物的不均匀膨胀和周期性的热冲击是导致岩石变质的根本原因。一定数量的循环后，弹性模量的下降和空隙空间的扩大阻止了对花岗岩的破坏加剧。纵波速度与力学参数之间具有良好的相关性，基于单轴抗压强度和弹性模量的损伤因子与超声方法获得的损伤因子呈正相关，说明可以利用超声方法。反映机械特性的变化。