Thermal damage is one of the fundamental mechanisms affecting the stability of rocks encountered in many deep geo-engineering ventures such as nuclear waste isolation, geothermal extraction etc. In the present study, the findings on influence of heating and subsequent cooling conditions on the fracturing and mechanical behaviour of an Indian granite are discussed. The granite samples from Jalore region of India were heated from room temperature to 600 °C followed by slow cooling and water quenching treatments. It was observed that rapid cooling through quenching had a greater impact on strength, elastic properties than slow cooling rate. Moreover, a drastic shift in terms of fracturing thresholds was witnessed, as a function of both temperature and sudden thermal shock experienced by rock at higher cooling rate. The simultaneous AE monitoring results suggested an early crack damage at higher thermal regimes. With help of microscopic observations, it was observed that inter-granular crack boundaries widened with increasing thermal damage experienced by minerals under both cooling conditions. However, the fracturing process was intense under rapid cooling treatment due to the invasion of water due to quenching which accelerated severe intra-crack growths, especially at higher thermal stress because of the rapid cooling rate than the slow cooling. The increased intensity of thermal cracks with temperatures and with variation in cooling rate was inferred as the primary reason for decay of rock characteristics. This was very well supplemented by decay in strength properties and changes in fracturing attributes of the tested granite as inferred from acoustic monitoring.

热损伤是影响岩石稳定性的基本机制之一，如核废料隔离、地热提取等许多深部地球工程项目。在本研究中，关于加热和随后的冷却条件对压裂和后续冷却条件影响的研究结果讨论了印度花岗岩的力学行为。来自印度贾洛雷地区的花岗岩样品从室温加热到 600°C，然后进行缓慢冷却和水淬处理。据观察，通过淬火快速冷却对强度、弹性性能的影响大于慢速冷却速度。此外，作为温度和岩石在较高冷却速率下经历的突然热冲击的函数，见证了压裂阈值的急剧变化。同时 AE 监测结果表明，在较高的热状态下会出现早期的裂纹损伤。在显微镜观察的帮助下，观察到晶间裂纹边界随着矿物在两种冷却条件下所经历的热损伤的增加而变宽。然而，在快速冷却处理下，由于淬火导致水的侵入，加速了严重的裂纹内生长，特别是在较高的热应力下，因为快速冷却速度比慢速冷却，压裂过程剧烈。随着温度和冷却速率的变化，热裂纹强度的增加被推断为岩石特性衰减的主要原因。