干热岩地热开发中，高温岩体经受反复的冷热循环，会导致热储层破裂、物理力学特性发生改变。为进一步探究温度和冷热循环方式对岩石特性的影响机制，对不同高温节点热处理的花岗岩试样分别进行了自然冷却、淡水和海水冷却的冷热循环处理，研究了物理力学指标和微观结构，建立了三种循环冷却方式的花岗岩单轴压缩损伤本构方程。结果表明：随温度和循环次数的增加，质量损失率的大小为淡水冷却>自然冷却>海水冷却，但在600 ℃条件下，严重的颗粒崩裂脱落会导致海水冷却岩样的质量损失超过自然冷却；弹性模量、抗压强度和抗拉强度不断减小，水冷对高温岩石的损伤较自然冷却更大，高温的损伤效应较循环次数更加明显，海水冷却岩样的微裂纹更加发育；损伤变量同时考虑温度和循环次数的影响，并加入损伤系数考虑淡水冷却和海水冷却的损伤效应。结合受荷损伤分析单轴压缩应力-应变曲线，与试验结果对比拟合程度较高，体现了模型的合理性。

During the geothermal development of dry hot rock, the high temperature rock mass is subjected to repeated cold and thermal cycles. It leads to the rupture of thermal reservoirs and the change of physical and mechanical properties. In order to further explore the mechanism of the influence of temperature and cooling-heating cycle on rock characteristics, the granite specimens subjected to different high temperature nodal heat treatment were treated with natural cooling, fresh water cooling and seawater cooling respectively. The physical and mechanical indexes and microstructure were studied. The damage constitutive equations of granite under uniaxial compression with three cooling cycles were established. The results show as follows. With the increase of temperature and cycle times, the mass loss rate is in the order of freshwater cooling > natural cooling > seawater cooling, but at 600 ℃, serious particle breakup and shedding cause the mass loss of seawater cooling rock sample to exceed that of natural cooling. The elastic modulus, compressive strength and tensile strength are decreasing. The damage of water cooling to high temperature rock is greater than that of natural cooling. The damage effect of high temperature is more obvious than that of cycle times. The micro-cracks of seawater cooling rock sample are more developed. The damage variables consider the effects of temperature and cycle times, and add the damage coefficient to consider the damage effects of freshwater cooling and seawater cooling. The uniaxial compressive stress-strain curves combined with damage analysis under load are compared with the experimental results in a high degree of fitting, which reflects the rationality of the model.