描述饱和土热固结过程的一个非线性模型及数值分析

基于多孔介质热–水–力耦合过程理论模型,给出饱和土的热固结控制方程及状态方程。考虑温度和孔隙水压力对排水模量的影响,建立了弹性模量的非线性表达式。且与已有热固结试验结果进行了对比,计算结果与试验结论基本相符。分析表明:饱和土试样中孔隙水渗透率的变化,对水压力消散及体应变的演化过程有非常明显的影响;等温排水固结过程中固体基质被压缩且体应变的变化较大,而升温不排水过程中固体基质有发生膨胀的趋势;重力影响下,饱和土试样上部体应变较下部体应变大;温度荷载加载等级的增加,使得饱和土试样中不断产生较大的孔隙水压力,且随孔隙水的排出整体平均体应变逐渐增大。

Nonlinear model and numerical simulation of thermal consolidation process of saturated soils

The governing equations and state equations for the thermosetting consolidation of saturated soils are given based on the coupled equations of thermo-hydro-mechanical coupling in porous media. And considering the influences of temperature and pore water pressure on the drained bulk modulus, the expression for nonlinear elastic modulus is established. The results are compared with those of the existing thermal consolidation tests, and the calculated results are in good agreement with the experimental results. The calculated results show that the change of permeability of water in soil specimens has a significant influence on the dissipation of water pressure and the evolution of volumetric strain. And the solid matrix is compressed and the bulk strain changes greatly in the isothermal consolidation process, whereas the solid matrix has a tendency to expand in the non-drainage heating consolidation process. Moreover, the upper bulk strain of porous media is larger than that of lower part due to the influences of gravity. The increase of temperature loading steps causes the pore water pressure to be continuously generated in the porous media, and the mean bulk strain increases with the discharge of pore water.