深部高温岩石往往会受不同冷媒介质作用,其力学特性的劣化极易诱发岩体工程灾害。考虑 3 种冷却方式 (高温炉中冷却、空气自然冷却及水中快速冷却),首先研究高温 (200~800 ℃) 花岗岩圆盘试样热−冷处理后其内部微裂纹分布及纵波波速变化规律。然后基于改进的 SHPB 试验系统,对不同热−冷处理后的花岗岩试样开展动态劈裂试验,研究不同加载速率下试样应力平衡状态、动态拉伸强度及变形破坏特性的演变规律。结果表明:① 岩石内部损伤程度随冷却速率增大而增大,水中冷却后试样波速下降率最大,内部产生的微裂纹数量最多。② 不同温度及冷却速率下试样动态拉伸强度与加载率呈指数正相关关系;200 ℃ 时,冷却方式对试样动态拉伸强度影响较小;而 400~700 ℃ 时,温度及冷却方式对试样动态拉伸强度影响较大,拉伸强度随温度及冷却速率的增大而降低。③ 温度及冷却方式对试样最先起裂位置处拉伸应变、起裂时间影响较大,最先起裂位置处拉伸应变随温度及冷却速率的增加而增加,起裂时间随温度及冷却速率的增加而缩短。④ 试样主要存在 2 种破坏模式:I 类为试样存在中心主裂纹及端部粉碎区;II 类破坏模式复杂,除了存在中心主裂纹及端部粉碎区外,还存在其他方向贯通裂纹。研究结果可为深部高温岩石工程的稳定性控制提供理论参考。

Deep high-temperature rock is often subjected to different cooling mediums, and the deterioration of its mechanical properties is easy to induce some rock mass engineering disasters. Based on the three cooling ways, cooled in anoven, cooled in air and cooled in water,firstly, the variations in the P-wave velocity and microscopic cracks of high temperature (200−800 ℃)granite after exposure to heating and cooling treatments were studied. Then, based on the modifiedSHPB test system, the dynamic tests were conducted by using the disc granite after exposure to heating and cooling treatments, and the stress equilibrium, dynamic tensile strength and deformation and failure of samples were investigated. Theresults  show  that  the  damage  degree  in  the  sample  increased  with  the  increase  of  cooling  rate,  and  the  water-cooledsamples exhibit the largest decrease in P-wave velocity and the largest amounts of newly-generated cracks. The relationship between the dynamic tensile strength and loading rate can be well-fitted using an exponential positive correlation. Thecooling rate has less influence on the dynamic tensile strength when the sample reaches 200 ℃. When the sample reaches400−700 ℃, the temperature and cooling rate have great effects on the dynamic tensile strength, and the dynamic tensilestrength decreases with the increase in temperature and cooling rate. The temperature and cooling rate have great influences on the dynamic tensile strain and fracture initiation time of the sample at the initiation position. The dynamic tensilestrain increases with the increase in temperature and cooling rate, and the fracture initiation time decreases with the increase in temperature and cooling rate. There are two failure types for samples with different heating/cooling treatments.Type I is the central main crack and the crushed zone at loading ends in the sample. Type II is very complex, there arecentral main crack, crushed zone at loading ends and cracks in other directions. The present results will be much helpfulfor providing the theoretical reference for the stability control of deep high-temperature rock engineering.