降雨诱发非饱和土地下水位上涨的耦合效应

Coupling effect of water table rising in unsaturated soil due to rainfall infiltration

降雨容易诱发地下水位上涨,从而引发多种危害.降雨诱发土体变形与渗流耦合,目前的研究多集中在土体耦合各场的变化规律,对土体水力耦合过程地下水位变化规律及影响因素研究较少.基于渗流理论、弹性理论及VG土-水特征曲线模型,建立了二维非饱土体的水力耦合的数值模型,从水力耦合的角度去研究降雨诱发地下水位上涨.该模型突破了饱和时的渗透系数是常量的局限,且适用于任意的土-水特征曲线表达式.通过算例对二维非饱和土渗流-变形耦合模型展开分析,并深入探讨了地下水位升高的耦合效应.计算结果表明:降雨强度、初始条件以及饱和渗透系数为变量等因素对地下水位上涨有显著的影响;位移最大值出现在地下水位以上,地下水位以下位移变化梯度相对较大.

Rainfall easily induces water table rising and leads to a variety of hazards.Infiltration and deformation are coupled during rainfall,while most of the current study focused on changes in seepage field and stress field and there are few studies on the water level and its influence factors.Based on the seepage theory, elastic theory and VG model,the two-dimensional hydro-mechanical model of unsaturated soil slopes was established.The water table rising was studied under rainfall condition based on the hydro-mechanical coupled theory.The model considered not only any soil-water characteristic curve,but also the variation of the coefficient of permeability at saturation.The two-dimensional hydro-mechanical model was analyzed through examples,and the coupling effect of water table change was deeply researched.The results indicate that the effects of rainfall intensity,initial conditions,and the saturated hydraulic conductivity have a great influence on the water table rising.The maximum displacement appear above the underground water level,the displacement gradient is bigger below the water table.