复杂裂隙岩体水–力耦合模型及溶质运移模拟

 在刚块弹簧法中引入非线性的裂隙本构关系，同时考虑裂隙法向的非线性应力变形关系、切向的剪切滑动以及剪胀效应，使得该方法可以较为真实地模拟裂隙开度在复杂应力作用下的变化。结合离散裂隙网络方法，建立采用隐式求解的复杂裂隙岩体的水–力耦合模型。该模型显式考虑裂隙存在，能很好地模拟裂隙网络在应力和渗流作用下的演化特征。在水力耦合达到平衡状态后，进行溶质运移分析，采用粒子追踪法模拟溶质在裂隙网络中随渗流的运移过程。根据所提出的模型编制相应程序，对DECOVALEX项目中的典型算例进行分析，研究不同应力条件对渗流以及溶质运移结果的影响以及不同应力条件下水力耦合的控制性机制。研究发现，低应力比条件和高应力比条件下对水力耦合作用起控制作用的分别是法向应力变形关系和剪胀效应。通过对比分析，验证模型的合理性。在此基础上，讨论高水头条件下考虑水力耦合效应的必要性。

NUMERICAL SIMULATION OF HYDRO-MECHANICAL COUPLING AND SOLUTE TRANSPORT IN COMPLEX FRACTURED ROCK MASSES

To realistically reflect changes in fracture aperture under complex stress conditions，a non-linear fracture constitutive model is introduced into rigid body spring model，taking into account the non-linear normal stress and deformation relationship，tangential shear slip and dilation effects. Based on this method and combining a discrete fracture network model，an implicit hydro-mechanical coupling model is established. Since fractures are explicitly considered，evolution of fracture networks during coupling process can be accurately simulated. A particle tracking method is used to simulate solute transport in fracture network after converge of coupling process is obtained. Corresponding program is developed in accordance with the proposed model. An example from DECOVALEX project is analyzed to study the impact of different stress conditions on flow and solute transport. Key mechanism controlling the coupling processes is studied；and it?s found that under low stress ratio and high stress ratio conditions，coupling process are mainly controlled by normal stress displacement relation and dilation effects respectively. By comparative analysis，the validity of the proposed model is verified. The necessity of considering hydro-mechanical coupling effect under high water head condition is discussed.