多年冻土路基水-热-力耦合理论模型及数值模拟

在建立多年冻土地区路基非稳态温度场控制方程、水分迁移的有限元控制方程和路基变形场及应力场计算模型的基础上，提出水-热-力耦合模型。以青藏公路唐南段K3393＋950的冻土路基为计算对象，得出了1月份路基温度场、水分场及应力场（变形场）的分布规律：路基温度场内部存在着未冻土核；水分场在温度梯度的作用下有向冻结冰锋线迁移的趋势；在负温条件下，土体的体积含冰量超过临界值时，将产生冻胀现象。研究结果表明，多年冻土地区路基的温度场、水分场及应力场一直处于动态变化中，路基的热状况、水分状况与变化规律及由此引起的应力重分布是引起道路冻害的主要因素。

Coupling model and numerical simulation of moisture-heat-stress fields in permafrost embankment

Based on the control equation of the non-stationary temperature field,the finite element control equation of the moisture movement and the two-dimensional numerical calculation model of the deformation and stress fields in the subgrade,this paper puts forward the coupling calculation model of the heat-moisture-stress fields.By the detail calculation example with the section of Qinghai-Tibet highway K3393 950 in January,this paper further explains the coupling process of the heat-moisture-stress fields and analyzes the interacting law of the temperature,moisture and stress fields in the subgrade.It is found that there is the unfreezing soil in the subgrade,the moisture trends to the freezing line under the temperature grads,once the ice volume exceed the critical value,the freezing damage will happen.The research results indicate that the temperature field,moisture field and stress field of the permafrost subgrade change all the time,the re-distributing of stress that is caused by the change of heat and moisture is the key factor for the frost damages.2 tabs,7 figs,6 refs.