基于微裂纹演化的煤层底板损伤破裂与渗流演化过程数值模拟

Numerical modeling of mining-induced fracturing and flow evolution in coal seam floor based on micro-crack growth

基于岩石细观尺度微裂纹扩展演化的物理机制,将微裂纹损伤张量引入到经典的Biot孔隙弹性理论中,推导了岩石细观损伤演化与岩石宏观力学性能及渗透特性之间的联系,建立了基于微裂纹演化的岩石渗流-应力-损伤耦合模型与控制方程。利用MATLAB软件编程,将该耦合模型嵌入到COMSOL软件中,实现了流-固耦合作用下岩石损伤破裂及渗流演化过程动态模拟的数值程序。在此基础上,进行了承压水体上采煤的数值模拟,系统研究了煤层开采过程中底板裂隙损伤演化、破坏形态和渗流演化规律,深入揭示了煤层底板"渗流通道"形成及突水灾变的复杂演化过程和机理。

Based on the mechanisms of micro-crack growth, a micro-crack damage tensor has been introduced to the classical Biot＇s poroelasticity theory to deduce the relation between the microscopic damage evolution of rock and the macroscopic mechanical and hydraulic properties and to establish thehydro-mechanical coupling model and governing equation based on the fracturing evolution. Then the proposed model has been programmed with MATLAB and COMSOL to simulate the failure process and flow evolution of rock under hydro-mechanical couplings. On this basis, numerical simulations of coal mining above a confined aquifer have been performed and the mining-induced fracturing, failure patterns and flow evolution in coal seam floor have been analyzed systematically. The numerical results clearly show how the groundwater inrush channel is formed.