降雨入渗对土堤渗流及边坡稳定性影响分析

Analysis on the influence of rainfall infiltration on embankment seepage and slope stability

为研究不同降雨类型作用下土堤渗流场及边坡稳定性,基于饱和非饱和渗流原理,采用有限元方法模拟土堤在前峰型、后峰型、中峰型及平均型降雨作用下渗流场,分析土堤的渗流特性及边坡稳定性。计算结果表明:降雨会使下游坡土体孔隙水压力(以下简称孔压)增大,堤身下游浸润线升高,在降雨的作用下监测点孔压总体上呈现先增大后减少并趋于稳定的趋势,下游坡安全系数逐渐降低,降雨停止以后下游坡安全系数小幅上升并趋于稳定;安全系数最终值后峰型(1.730)<中峰型(1.745)<平均型(1.756)<前峰型(1.757),后峰型降雨对边坡孔压变化幅度和安全系数影响最大。研究成果可为堤防防汛抢险提供参考。

In order to study the seepage field and slope stability of soil embankment influenced by different rainfall types,based on the principle of saturated and unsaturated seepage,the finite element method was used to simulate the seepage field of soil embankment under the action of front peak,back peak,middle peak and average rainfall,and the seepage characteristics and slope stability of soil embankment were analyzed.The calculation results show that rainfall increased the pore water pressure of the downstream slope soil and the infiltration line of the downstream embankment.Under the action of rainfall,the pore water pressure of the monitoring points generally increased first,then decreased,finally tended to be stable,and the safety factor of the downstream slope gradually decreased.After the rainfall stoped,the safety factor of the downstream slope slightly increased and tended to be stable.The final value of safety factor was posterior peak type(1.730)<middle peak type(1.745)<average type(1.756)<front peak type(1.757).The rainfall of posterior peak type had the greatest influence on the variation range of pore pressure and safety factor of slope.The research results can provide reference for flood control and emergency rescue of embankments.