考虑渗气渗水函数的非饱和土固结性状研究

大坝蓄水所引起的水环境变化会诱发其周边建筑物地基产生显著的沉降变形,要合理预测其沉降过程,则需研究非饱和土地基的固结性状。为此,基于混合物理论,在非饱和土的水、气两相渗流-变形耦合方程组中,采用离散线性化的方法引入了渗气渗水函数和持水曲线方程,给出了考虑渗气渗水系数比值变化的一维固结微分方程组,进而采用积分变换方法求得非饱和土层孔隙水、气压力消散及其沉降变形的解析解。最后,选取水、气相互连通的非饱和土层典型算例,通过与已有文献所述未考虑渗气渗水系数比值变化的解析解、有限差分解的计算结果对比发现:本文解析解因考虑了水、气渗流相互作用对非饱和土固结过程的影响,故其计算的孔隙水、气压力消散曲线与沉降变形曲线较已有文献解析解更接近于有限差分解的计算曲线。

Analysis of consolidation in unsaturated soils considering air-water permeability function

The change of hydrogeological characteristics due to the filling of the reservoir of dam will induce significant foundation settlements of surrounding buildings.For the sake of reasonable prediction of the settlement,it is necessary to analyze the consolidation behavior of unsaturated soils.In response,based on the theory of mixture,the air-water permeability function and water retention equation were discrete linearized in the coupled equations of seepage-deformation.Then,the one-dimensional consolidation differential equations considering the variation of air-water permeability were obtained and analytically solved using integral transform method.Finally,a typical example of unsaturated soil layer in which air and water are interconnected was given to compare among the previous analytical solution without considering the variation of air-water permeability,the proposed solution and the finite difference solution.The results show that the influence of air-water permeability interaction on the consolidation process of unsaturated soil is considered in the proposed analytical solution,so that the calculated dissipation of pore water and air pressure and evolution of settlement by the proposed solution are closer to the corresponding calculated curve by finite difference solution than the previous solution.