深部高温高应力岩石动态断裂特征及微观破裂机理

Deep rock mass is in an environment of high temperature and ground stress. Some dynamic disturbance is inevitable in the process of deep deposit mining, such as rock bursting, mechanical drilling and high stage mining, etc. Meanwhile, some dynamic fracture like slabbing, spalling and rock burst may usually occur. Therefore, it is necessary to investigate the dynamic fracture characteristics and microscopic failure mechanisms of rock under the coupled effect of high temperature, high ground stress and dynamic disturbance. This project makes full use of laboratory tests, theoretical analyses and numerical simulation methods, considering the factors of high temperature, high stress and dynamic disturbance, to study the fracture mechanics characteristics and micro fracture mechanisms of rock. A dynamic fracture failure criterion of rock under the coupling of temperature and stress will be established and the occurrence mechanism will be revealed for the dynamic fracture failure of highly stressed rocks under the action of temperature. The relationship between micro and macro characteristics of dynamic fracture will be obtained, and the microscopic mechanism of temperature on dynamic fracture failure of highly stressed rock can be expounded. The aim of the project is to provide a theoretical basis and technical guidance for the effective control and use of dynamic instability during the excavation of deep rock mass.

深部岩体处于高地温和高应力环境，同时，深部矿岩开采过程中还会受到爆破崩矿、机械凿岩和高阶段落矿等产生的动力扰动，使得岩体发生岩爆、板裂和片帮等断裂破坏，因此需研究高温、高应力与动力扰动作用下岩石的动态断裂特征及破坏机理。项目充分运用室内实验、理论分析和数值模拟等方法，综合考虑高温、高应力和动力扰动等因素共同作用下岩石的断裂力学特征及微观破裂机理开展研究，建立温度应力耦合作用下岩石动态断裂破坏准则，揭示温度作用下高应力岩石动态断裂破坏的诱发机理，获得动态断裂破坏微观与宏观特征之间的关系，阐明温度对高应力岩石动态断裂破坏的微观机制，为深部岩体工程开挖过程中动力失稳控制提供理论依据。

高温岩石结构的断裂破坏问题已成为深部工程中亟需科技攻关的热点和难点之一。本项目充分运用室内实验、理论分析和数值模拟等手段，对高温、高应力和静、动力扰动等因素共同作用下岩石的断裂特征开展了系统研究，取得了以下主要研究结果：.（1）研究了高温处理对花岗岩I型和II型动态断裂韧度的影响。结果表明，随着加载速率的增加，岩石I型和II型动态断裂韧度均呈现线性增加趋势；但同一加载速率条件下，随着温度增加，岩石I型断裂韧度单调下降而II型动态断裂韧度呈现先增加后下降的趋势；.（2）研究了循环冲击载荷条件下热处理花岗岩损伤演化和能量耗散规律。结果表明，随着处理温度增加，岩石破坏所需循环冲击次数逐渐减少，岩石破坏时的总反射能呈现先增加后降低趋势，而透射能和吸收能呈现单调下降趋势；.（3）研究了静态加载条件下温度对花岗岩I型及I+II复合型断裂行为的影响。结果表明，随着处理温度的增加，花岗岩断裂模式从脆性断裂转变为了塑性断裂，岩石双K断裂韧度和复合型断裂韧度也随之降低；热处理不会改变花岗岩复合型断裂韧度和裂纹起裂角随复合系数的变化规律，复合型断裂韧度和裂纹起裂角可以通过同一的广义最大周向应力准则进行预测。.（4）研究了温度冲击对花岗岩损伤和断裂韧度的影响。结果表明，岩石初始温度越高，受液氮和水冷却处理时损伤越大，断裂韧度越低；微波功率越大，加热时间越长，岩石损伤越大，断裂韧度越低；岩石温度越高，循环冷却次数越多，岩石损伤越大，断裂韧度越低。.（5）提出了岩石温压耦合性能测试方法和仿真测试系统，实现从室内试验和数值试验角度探究高温下岩石的动态力学特性。