非饱和土层中污染物运移过程的数值分析

针对填埋场下部为压实粘土衬里、非饱和土层和含水层的三层结构体系,建立了描述填埋场污染物运移的一维控制方程,在控制方程中考虑了压实粘土衬里的平衡非线性吸附方程与非饱和土层的线性吸附方程。采用数值法求解控制方程,通过变动参数探讨了污染物在三层结构体系中运移过程的各种影响因素。

Numerical analysis of transport of landfill pollutants in unsaturated soil layer

The landfill site was idealized as three-layer strata composed of a compacted clay liner, an underlying unsaturated deposit and a layer of aquifer below the landfill. For such a system, one-dimensional mathematical equation for governing landfill pollutant transport through the three-layer strata was established. In the proposed model, steady-state unsaturated moisture distributions were employed in the dispersion-advection equation to simulate the transient distribution of contaminant in the strata beneath landfill. For the compacted clay liner, nonlinear equation of equilibrium sorption for the contaminant was employed, while the linear equation of equilibrium sorption was used for the unsaturated soil layer. The proposed equation of pollutant transport was numerically solved and comparative computations for varying parameters were made to examine the effect of various factors on the transport process of pollutants in each individual layers of the strata.