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本文在建立冻土水热耦合迁移的数学模型基础上，采用全隐式有限差分格式并用线性化迭代方法求解。边界条件处理采用半控制容积法，时间步长根据迭代情况自动调节，求解过程中为防止振荡过大采用松驰迭代等措施。通过计算与实验结果对比，取得较好效果，表明采用的数学模型及数值计算方法可靠。用此模型模拟了非实验状态下（历时３０ｄ及表面温度降至－２０°Ｃ）的土壤冻结过程。模拟显示温度分布随冻结历时的加长而变缓，最后趋于线性分布，随上、下表面温差的加大而变陡；水分分布基本形状并不随时间及上、下表面温差而变，只是冻深及上迁水量随历时加长、温差加大而增大。
Based on the mathematical model of hydrothermal coupled migration of permafrost, a fully implicit finite difference scheme is adopted and solved by linear iterative method. The boundary condition is processed by semi-controlled volumetric method, the time step is automatically adjusted according to the iterative conditions, and the relaxation iteration is used to prevent the excessive oscillation during the solution. Through the comparison between calculation and experimental results, good results are obtained, which shows that the mathematical model and the numerical calculation method are reliable. The model was used to simulate the soil freezing process under non-experimental conditions (lasting 30 days and decreasing the surface temperature to -20 ° C). The simulation shows that the temperature distribution becomes slower with the prolongation of the freezing duration and finally tends to be linear with the steepness as the temperature difference between the upper and lower surfaces increases. The basic shape of the water distribution does not change with time and the temperature difference between the upper surface and the lower surface, Deep and upward movement of water with longer duration, temperature increases and increases.