不同围压作用下非均匀岩石水压致裂过程的数值模拟

从岩石细观非均匀性的特点出发，提出一个描述非均匀材料渗流和破裂相互作用的数值模型。在这个数值模型中，单元的力学、水力学性质根据统计分布而变化，以体现材料的随机不均质性，材料在开裂破坏过程中流体压力传递通过单元渗流，损伤耦合迭代来实现。算例表明，该模型能较好地模拟出岩石类材料在水力压裂作用下，微结构非均匀分布和不同围压比对破裂模式、失稳压力的影响，非均匀性导致试件的开裂压力、失稳压力明显不同，裂纹扩展路径不规则发展，模拟结果和实验结果较为一致。

Numerical simulation of hydraulic fracturing process in heterogeneous rocks under different confining pressures

Hydraulic fracture is the classical coupling action of seepage-damage and it is very important of understanding the hydraulic fracture mechanisms to deal with the problems of rock seepage stability, such as dam instability and water outburst. On the heterogeneous characteristics of rock at microscopic level, in this paper, a numerical model, which couples the seepage and the failure process, is developed to study hydraulic fracturing phenomenon in permeable and heterogeneous rocks. In this model, material is discretized into a large number of elements with the same size and different mechanical and permeable parameters in order to represent heterogeneity of rock. A coupling analysis of seepage and damage under hydraulic fracturing on rock is performed to simulate the fracture process of rock. The numerical analyses given in this paper indicate that this model is capable in simulating the heterogeneous distribution of stress and permeability of rock subjected to hydraulic fracturing under different confining pressure. The modeling results suggest that the fracture initiation and propagation, the roughness of fracture path and the breakdown pressure are influenced considerably by the heterogeneity of the rock, the numerical results can agree well with the relevant experimental data.