非饱和夹层土中水-气-热-力多场耦合分析

Multi field coupling analysis of water-gas-thermal-mechanical in unsaturated intercalated soil

在修筑公路时,不可避免涉及路基质量控制问题。针对非饱和夹层路基土中水-气-热-力多场耦合问题进行研究,在质量守恒和能量守恒方程中创造性地引入水蒸气和干燥气体非对流通量的影响因素,同时在耦合过程中考虑固体基质和液相的可压缩性的影响,并在动量守恒方程中考虑了土体的热应变与湿应变,利用COMSOL对非饱和夹层土的水-气-热-力多场耦合模型进行求解,将数值解与试验结果进行了对比,验证了所建立数学模型的准确性。基于该数学模型,分析了单层非饱和土与非饱和夹层土体在温度梯度和水力梯度作用下,土体中水分场、气体场以及温度场分布规律的不同,为路基的建设和保护提供了理论指导和依据。

Subgrade quality control is an inevitable part of highway construction.The research was aimed at the water-gas-heat-mechanical multi-field coupling in unsaturated interlayer subgrade soil.The factors affecting the non-convective fluxes of water vapor and dry gas were creatively introduced into the mass and energy conservation equations,and the effects of compressibility of solid matrix and liquid phase were considered in the coupling process.The thermal and wet strains of soil were also considered in the momentum conservation equation.Finally,COMSOL was used to solve the water-air-thermal-mechanical multi-field coupling model of unsaturated intercalated soil,and the numerical solution was compared with the experimental results,verifying the accuracy of the mathematical model.Based on this mathematical model,the differences in the distribution of water,gas,and temperature fields in single-layer unsaturated soil and unsaturated intercalated soil under temperature and hydraulic gradients were analyzed.This analysis provides theoretical guidance and a basis for subgrade construction and protection.