岩体水力劈裂的应力-渗流-损伤耦合模型研究

Research on stress-seepage-damage coupling model of hydraulic fracturing for rock mass

利用无单元法追踪裂纹扩展的优势研究模拟岩体水力劈裂的数值分析模型。定义损伤变量以描述岩体的损伤程度对岩体渗透性和强度的影响,建立了岩体水力劈裂的应力-渗流-损伤耦合分析模型,并编制了基于无单元法的计算程序。综合考虑应力、渗流及损伤之间的相互作用影响,分析了具有初始裂纹的岩体平面应力模型的裂纹扩展过程,指出考虑渗流作用时的裂纹扩展角大于不考虑渗流作用时的裂纹扩展角。同时,裂纹内水压力和渗流的作用对于裂纹的扩展方向和扩展长度具有较大的影响。

In virtue of the great advantages of the Element-Free Method （EFM） in crack propagation tracing, the numerical method is studied for simulating the hydraulic fracturing of rock mass. The influence of damage degree on its permeability coefficient and intensity of rock mass is described by defining a damage variable. Then a stress-seepage-damage coupling analysis model is established for simulating the hydraulic fracturing of rock mass, and the corresponding computation program is developed based on the EFM. Synthetically considering the influence of the interactions of stress, seepage and damage of rock mass, the crack propagation process is forecasted and analyzed for a plane stress model with an original crack. It is concluded that crack propagation angle when considering seepage is bigger than the one when not considering seepage. In addition, it is found that the action of water pressure and seepage in crack can bring forth the effect on propagation direction and length of crack. The calculational result here more approaches the one of laboratory experiment in reference.