热损伤作用下岩石的宏细观力学响应及其裂纹扩展机制

The physical and mechanical behaviors of rocks after exposure to high temperature are a fundamental topic of great interests to many researchers in rock mechanics. However, the thermal cracking mechanism of rocks under thermal stress is still not completely captured at present. The research in this study is mainly focused on the macro- and micro-mechanical behaviors and thermal cracking mechanism of rocks under the effect of thermal damage. Based on laboratory tests and microscopic testing methods, the relation between the microstructure damage and mechanical properties is studied for rocks after exposure to high temperature. The mechanism of thermal cracking is also studied. A quantitative method is proposed to characterize the initial thermal induced microcrack damage. A micro-mechanics based damage model is established which can consider the effect of initial thermal induced microcrack damage. Based on the discrete element method, the micro-structure of rocks is exactly modeled. The distribution, type, and position of microcracking and the corresponding mechanical behavior are simulated using the numerical model. The influences of heterogeneity and initial thermal induced microcrack damage on the mechanical behavior and acoustic emission property are studied. The study can provide an important theoretical contribution to the issue of strength and deformation evaluation of rocks under complex thermal damage effects and complex stress paths.

热损伤作用下岩石的物理力学性质是岩石力学领域的基础科学问题，然而岩石在热应力作用下的裂纹扩展机制仍未能完全掌握。本项目以热损伤作用下岩石的宏细观力学特性以及裂纹扩展机制为研究对象，结合宏观力学实验和细观测试手段，研究热损伤作用下岩石的细观损伤演化与宏观力学性质之间的联系，揭示热损伤微裂纹的扩展机制。提出合理可行的初始微裂纹损伤评价方法，并建立可以考虑初始微裂纹损伤的细观损伤力学模型。基于离散元方法，实现岩石细观构造的精细化模拟，模拟岩石在热损伤作用下的裂纹分布形式、裂纹类型和裂纹扩展规律以及相应的宏观力学性质，分析岩石非均质性和初始微裂纹损伤对宏观力学特性以及声发射性质的影响，揭示岩石变形过程中的微观裂纹扩展机制，为解决工程中复杂热损伤作用及复杂荷载条件下的岩石强度与变形性质评价提供理论方法。

热损伤作用下岩石的物理力学性质是岩石力学领域的基础科学问题，然而岩石在热应力作用下的裂纹扩展机制仍未能完全掌握。本项目研究了热损伤作用下岩石的宏细观力学特性以及裂纹扩展机制。通过本项目的研究，热损伤作用下岩石的细观损伤演化与宏观力学性质之间的联系，揭示热损伤微裂纹的扩展机制。提出合理可行的初始微裂纹损伤评价方法，并建立可以考虑初始微裂纹损伤的细观损伤力学模型。基于离散元方法，实现岩石细观构造的精细化模拟，模拟岩石在热损伤作用下的裂纹分布形式、裂纹类型和裂纹扩展规律以及相应的宏观力学性质，分析岩石非均质性和初始微裂纹损伤对宏观力学特性以及声发射性质的影响，揭示岩石变形过程中的微观裂纹扩展机制，为解决工程中复杂热损伤作用及复杂荷载条件下的岩石强度与变形性质评价提供理论方法。