Experiment research of the influence of different cooling times on the drillability of high-temperature granite

To study the drillability and microscopic damage changes of granite after high temperature exposure and to study the influence of different cooling times on drillability after high temperature exposure, granite for high-temperature heat treatment was cooled by different times (2 h, 4 h, 24 h, and 48 h). Through the drillability experiment and the cast thin identification of the processed rock samples, the influence law and mechanism of high temperature on the drillability of granite were obtained, and the influence of different cooling times on the granite drillability was also investigated. The research results show that granite always maintains a high drillability index under the constraints of heat treatment not exceeding 500℃ and natural cooling for 2 h. After cooling 4 h, 24 h, and 48 h, the impact of high temperature on drillability shows three stages (First degradation stage, strengthening stage, second degradation stage). The location and number of microcracks affect the difficulty of rock resistance