降雨入渗过程的水-气二相流模型研究

本文根据多孔介质中水、气的质量守恒定律，结合多相流理论，建立了求解饱和-非饱和渗流的水-气二相流数学模型，并采用积分形式的有限差分法和NewtonRaphson迭代方法进行数值求解，提出了各种边界条件，包括水相、气相和降雨入渗边界的数学处理方法。利用上述模型对土柱试验进行模拟，将计算结果与试验数据比较，验证了模型的正确性；然后对土质边坡降雨入渗过程进行计算，得到孔隙水压力、孔隙气压力和毛细压力的变化过程，其变化规律符合实际，实现了降雨入渗的水-气二相渗流过程，为定量研究空气阻力对入渗水流的影响提供有效途径。

Water-air two-phase flow model for numerical analysis of rainfall infiltration

Based on the multi-phase flow theory and the law of mass conservation for water and air in porous media a numerical model for describing the saturated-unsaturated filtration in soil is established. The integral of finite difference method and Newton-Raphson iterative method are applied to numerically solve the governing equations of water-air two-phase flow in saturated-unsaturated porous media. The approaches to boundary condition treatment and obtaining unsaturated hydraulic parameters are proposed. The validity of the model is verified by the simulation for a filtration experiment of soil column. The process of rainfall infitration in a soil slope is simulated numerically. The variation of pore water pressure, pore air pressure and capillary pressure in the process of rainfall infitration are obtained.