为模拟边坡在库水涨落和降雨作用下的渐进破坏过程,发展基于连续介质离散元的双重介质渗流应力耦合模型。它分为固体计算模型、孔隙渗流应力耦合模型和裂隙渗流应力耦合模型3个部分。固体计算模型能够反映地质体的破坏规律,可以模拟从连续到非连续的破坏过程;孔隙渗流应力耦合模型可以方便地计算出自由水位线(浸润线)的位置;裂隙渗流应力耦合模型可以避免由于不连通裂隙(孤立裂隙)存在所导致的收敛性问题;假设只考虑库水涨落和降雨的最终状态,裂隙渗流产生的水头分布和由库水涨落所引起的水头改变作为孔隙渗流的变边界条件,从而实现孔隙渗流场和裂隙渗流场的耦合。典型算例计算结果表明,基于连续介质离散元的双重介质渗流应力耦合模型对于库区古滑坡的研究是很有效的。
To simulate the progressive failure process of the slope in water level fluctuation and rainfall conditions, a coupled fluid flow and stress computation model of dual media is established based on continuum-medium distinct element method. It contains solid calculation model, pore hydromechanical coupling model and fissure hydromechanical coupling model. Solid calculation model could reflect failure regularity of the geologic body, also could simulate the process from continuum to discontinuum. Pore hydromechanical coupling model could calculate the location of phreatic surface conveniently. Fissure hydromechanical coupling model could avoid convergence problem caused by isolated fissure. Considering the final states of the water level fluctuation and rainfall, the waterhead distribution caused by fissure seepage and water level fluctuation in reservoir are regarded as the variable boundary condition, thus implementing the coupling analysis for pore and fissure seepage flow field. Typical example computational results show that a coupled fluid flow and stress computation model of dual media based on continuum-medium distinct element method is very effective for the analysis of reservoir ancient landslide.