考虑冻土相变的非稳定温度场-渗流场耦合有限元分析研究

对冻土相变时非稳定温度场-渗流场耦合的有限元计算方法进行改进,根据土壤冻结特征曲线计算和修正孔隙含冰量,同时提出了未冻土体积含水量对温度导数的修正方法和加速迭代收敛速度的新方法,消除了冻土温度场-渗流场耦合计算中出现的数值振荡现象,加快迭代收敛速度,使其能够适用复杂多变边界条件下土体的冻结、融化计算。最后通过两个数值算例用此方法与试验值进行对比分析,验证了本文方法的可靠性和有效性。

FEM Analysis Research on Unsteady Temperature-seepage Coupling System of Frozen Soil Phase Changing

Considering the change of frozen soil phase,the finite element method of unsteady temperature field-seepage field coupled problem was improved.According to the soil freezing characteristic curve,the pore ice containing volume was calculated and fixed.At the same time,a correction method of temperature derivate unfrozen soil’s water volume,and a new method accelerating the convergence speed were put forward,to eliminate the numerical oscillation phenomena that appears in the frozen soil’s temperature field-seepage field coupling calculation,and accelerate the convergence speed.Finally,two numerical examples were compared with the experiments to verify the reliability and effectiveness of the method.