摘要
降雨是工程区域堆积体边坡失稳的重要诱因,如何评价降雨条件下饱和-非饱和渗流对堆积体边坡稳定性的影响,其挑战在于准确获取堆积体的非饱和渗流参数。以梅家台滑坡典型治理工程为研究对象,采用饱和-非饱和有限元分析,并基于监测资料对渗流场动态反演,准确获得了非饱和水力参数和边界水位,进而采用极限平衡法对滑坡稳定性演化分析。结果表明:坡体后缘补给水位在692.0~694.5 m内动态变化,在后缘补给和降雨入渗作用下坡体内地下水位变幅为3.0~12.0 m;排水措施实施后地下水位下降9.0 m,且变幅降为1.0~5.5 m,同时在暴雨条件下,滑坡中部堆积薄弱带暂态饱和区范围减小84.5%,坡脚饱和区也被抑制到一号公路以下,发挥了很好的排水降压作用;滑坡存在沿中部薄弱带浅层滑动、沿下部前缘浅层滑动、沿老滑带从一号公路剪出3种失稳模式,降雨入渗时稳定性明显下降,稳定系数分别降低至0.82、0.99、0.98,小于稳定安全系数1.05,综合治理措施下,稳定系数分别增加0.28、0.13、0.19,目前稳定系数分别为1.10、1.12、1.17,各个失稳模式稳定系数均大于稳定安全系数,滑坡处于稳定状态。研究成果可为类似工程治理设计和渗流稳定分析提供参考。
Rainfall is an important cause of deposit slope instability in engineering area.How to evaluate the influence of saturated-unsaturated seepage flow on the stability of deposit slope under rainfall condition?The challenge lies in accurately obtaining the unsaturated seepage parameters of deposit body.Taking Meijiatai landslide control project as the research object,unsaturated hydraulic parameters and boundary water level are obtained by using saturated-unsaturated finite element analysis and dynamic inversion of seepage field based on monitoring data,and then limit equilibrium method is used to analyze the change of landslide stability.The results show that the groundwater level at the back edge of the slope changes dynamically from 692.0 m to 694.5 m,and the groundwater level in the slope varies from 3.0 m to 12.0 m under the influence of the back edge recharge and rainfall infiltration.After the drainage measures were implemented,the groundwater level decreased by 9.0 m,and the variation amplitude was reduced to 1.0~5.5 m.At the same time,the range of the transient saturation area of the weak accumulation zone in the middle of the landslide was reduced by 84.5%,and the saturated area at the foot of the slope was suppressed below Highway 1,which played a great role in drainage and pressure reduction.There are three instability modes of landslide:shallow slide along the central weak zone,shallow slide along the lower front,and cut out from Highway 1 along the old slide zone.The stability decreases significantly during rainfall infiltration,and the stability coefficient decreases to 0.82,0.99,and 0.98 respectively,which is less than the stability safety coefficient of 1.05.Under comprehensive management measures,the stability coefficients are increased by 0.28,0.13 and 0.19 respectively,and the current stability coefficients are 1.10,1.12 and 1.17 respectively.The stability coefficients of each instability mode are greater than the stability safety coefficient,and the landslide is in a stable state.The research results can provide reference for similar engineering management design and seepage stability analysis.
作者
李宏伟
高维鸿
胡冉
LI Hong-wei;GAO Wei-hong;HU Ran(Wuhan University State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan 430072,Hubei Province,China;Wuhan University Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of the Ministry of Education,Wuhan 430072,Hubei Province,China)
出处
《中国农村水利水电》
北大核心
2024年第8期150-159,共10页
China Rural Water and Hydropower
基金
国家自然科学基金(51988101)。
关键词
降雨入渗
饱和-非饱和渗流
排水措施
边坡稳定
梅家台滑坡
rainfall infiltration
saturated-unsaturated seepage flow
drainage measure
stability of slope
Meijiatai landslide
