垃圾渗滤液污染的耦合动力学行为及数值模拟

垃圾渗滤液在填埋场中的运移过程受复杂地质环境（渗流场、应力场和浓度场）作用的影响。基于多孔介质流-固耦合及溶质运移理论，建立了垃圾渗滤液运移过程的多场耦合数学模型，并采用P-R隐式差分方法，给出了耦合模型的数值格式。通过编制的计算程序，对多场耦合作用下填埋场内渗滤液的浓度分布进行了动态模拟。模拟结果表明：随着时间的推移，对流作用对渗滤液迁移的影响更加明显；应力场耦合作用下的浓度变化速率相对降低，主要是由于考虑骨架变形后，孔隙介质渗透率的降低直接导致流体平均流速减慢而造成的。因此，对渗滤液迁移规律的研究必须同时考虑渗流场、应力场和浓度场的耦合作用，以此为准确预测渗滤液的污染情况提供更可靠的理论依据。

COUPLED DYNAMICS BEHAVIOURS AND NUMERICAL SIMULATION OF LEACHATE POLLUTION

Leachate transport in landfill is affected by complex geological environment. Based on fluid-solid coupled and solute transportation theory in porous media, multi-field mathematical model has been developed for describing leachate transportation, and the numerical model is given by applying P-R implicit finite difference method. The program is applied to simulate the concentration distribution of leachate in landfill, which has been presented under coupling multi-field effect. Numerical results show the convection effects become significant, especially as time passed. The rate of variation of concentration under stress field effect is lower than without coupling effect. The mainly reason is that a decrease of permeability leads to the mean velocity of the fluid slowed down with the skeleton deformation in porous media. Therefore, coupling the seepage field, stress field and concentration field is very important to study the seepage law of leachate transport. It will provide more reliable evidence for forecasting water quality polluted by leachate in aquifer.