降雨条件下非饱和土坡三相流模型的渗流-变形耦合分析  

Seepage-deformation Coupling Analysis of Unsaturated Slope Three-phase Flow Model Under the Rainfall

作　　者：杨天娇 王述红[1] 张雨浓 佟可蕙[1] YANG Tianjiao;WANG Shuhong;ZHANG Yunong;TONG Kehui(School of Resource and Civil Engineering,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学资源与土木工程学院,辽宁沈阳110819

出　　处：《应用基础与工程科学学报》2021年第2期355-367,共13页Journal of Basic Science and Engineering

基　　金：国家自然科学基金项目(51474050,U1602232);地质灾害防治与地质环境保护国家重点实验室项目(SKLGP2014K011);辽宁省高等学校优秀人才支持计划项目(LN2014006)。

摘　　要：土质边坡降雨入渗的过程中伴随着地下水渗流的推进、孔隙气体迁移和边坡土体变形,因而涉及非饱和土体固-液-气三相耦合的作用.首先基于非饱和土力学基本理论、土-水特征曲线模型,在考虑气相对降雨入渗过程的影响下,建立了考虑孔隙介质可压缩性的二维非饱和土坡固-液-气三相渗流-变形耦合控制方程组.然后利用COMSOL Multiphysics软件的PDE平台,将所建立的耦合控制方程的数值模拟结果与经典Liakopoulos砂柱排水的试验结果进行比较,验证了本文所建立的三相耦合控制方程其正确性.最后对已建好的耦合模型求解分析,对比探讨两相和三相耦合计算模型对渗流场和位移场的影响.模拟结果表明:孔隙水压力随降雨时间的增加而逐渐增大,孔隙气体迁移和土体变形对边坡降雨入渗的推进起阻滞和延缓作用,揭示了固-液-气三相渗流-变形耦合模型能够更真实的反应降雨条件下土坡的变化特征,从而对非饱和土质边坡的灾害预警提供指导作用.The process of rainfall infiltration in soil slope was accompanied by groundwater seepage propulsion,pore gas migration and slope soil deformation,thus this process involved solidliquid-gas three-phase coupling of unsaturated soil.Firstly,based on the basic theory of unsaturated soil mechanics and soil-water characteristic curve model,the two-dimensional unsaturated soil slope solid-liquid-gas three-phase seepage-deformation coupled control equations considering the compressibility of porous media was established under the influence of gas-phase to rainfall infiltration process.Then,using the PDE platform of COMSOL Multiphysics software,the numerical results of the established coupled control equations were compared with the experimental results of the classical Liakopoulos sand column,and the correctness of the three-phase coupled control equations established in this paper was verified.Finally,the established coupling model was analyzed,and the effects of two-phase and three-phase coupling models on the seepage field and displacement field were compared.The results show that the pore water pressure increases with the increase of rainfall time,and pore gas migration and soil deformation can delay the propulsion of the rainfall infiltration.It is revealed that the solidliquid-gas three-phase seepage-deformation coupling model can more truly reflect the characteristics of soil slope changes under rainfall,so as to provide some guidance for the disaster warning of unsaturated soil slope.

关 键 词：降雨入渗 固-液-气耦合 渗流-变形耦合 非饱和土质边坡 孔隙水压力 孔隙气压力 

分 类 号：TU43[建筑科学—岩土工程]