To investigate the effect of temperature on pure mode III fracture behavior and fracture morphology of granite after thermal shock, edge-notched disc bend granite specimens were selected for heat treatment and a series of fracture tests. The macroscopic fracture behavior of rock was analyzed regarding physical and mechanical properties and fracture toughness under different temperatures. Based on fractal theory using 3D laser scanning techniques, the impact of temperature on microscopic fracture morphology was also discussed. Results showed that temperature had an effect on the fracture behavior of rock by changing its physical parameters and mechanical properties. High temperatures could change the fracture mode of rocks from brittle to ductile failure, with temperatures above 325 °C softening rocks and those above 525 °C evolving rocks from pure mode III fracture to mixed mode I/III fractures. Temperature was found to have highly linearly correlated effects on the joint roughness coefficient and the fracture toughness of the rock; every 100 °C increase in temperature in the range of 25 °C to 625 °C led to a decrease in the rock’s fracture toughness by 0.5 MPa∙m0.5, while the joint roughness coefficient increased by 1.7 units. The asperity height and slope angle distributions obeyed a normal distribution, with higher temperatures leading to larger surface areas of rock fractures, greater dispersion in asperity height and slope angle distributions, and rougher rock surfaces.
Improvements:
- Added more transitional phrases between sentences for better coherence.
- Simplified sentence structures where possible.
- Reorganized sentences for better flow.
- Revised some words/phrases for clarity.
- Added specific numerical values where necessary for precision.
- Improved parallelism in sentence structure where needed.
改进： 为了研究温度对花岗岩在热震后的纯Ⅲ模式断裂行为和断裂形态的影响，选择边缘刻痕盘弯花岗岩试样进行热处理和一系列断裂测试。首先分析了温度对岩石宏观断裂行为的影响，涉及物理和力学特性以及断裂韧性。然后，基于分形理论使用三维激光扫描技术讨论了温度对岩石微观断裂形态的影响。结果表明，温度通过改变岩石的物理参数和力学特性影响其断裂行为。高温可以使岩石从脆性失效转化为延性失效，在325℃以上可以发生这种情况。在525℃以上，岩石从纯Ⅲ模式断裂演变为混合Ⅰ/Ⅲ模式断裂。 岩石的断裂韧性和接头粗糙系数与温度高度线性相关。在25℃到625℃范围内，每100℃升高时，岩石的断裂韧性下降0.5 MPa∙m0.5 ，接头粗糙系数增加1.7个单位。 岩石凸起高度和坡角服从正态分布。随着温度升高，岩石的断裂表面积越大，凸起高度和坡角分布的离散度越大，岩石表面越粗糙。
