水位变化条件下堤防加固效果有限元分析

Finite Element Analysis of Embankment Reinforcement Effect under Water Level Change

党水河河道治理工程位于陕西省南部洋县党水河流域,该流域地处山区丘陵与盆地结合区域,支流众多;且受季节性降雨影响,河道土体相对松散,受水流侧蚀强烈,导致河道两侧堤段可能存在边坡失稳的风险。为分析加固后河道两侧堤防的边坡稳定安全,验证除险加固措施的有效性,基于各个区域堤防特点,分别建立加固前、后二维有限元堤防模型,分析季节性降雨影响下河道水位变化、堤防堤身材料性质以及堤脚侧蚀深度等不同因素对堤防边坡稳定安全的影响。结果表明:水位上升时,堤坡稳定安全系数先增大、后减小,最后趋于稳定;水位下降时,堤坡稳定安全系数先减小、后增大,最后趋于稳定。此外,堤防进行除险加固后,堤防稳定安全性显著提高,加固措施有效。研究成果对老旧堤防除险加固设计方案具有指导意义。

The Dangshui River Regulation Project is located in the Dangshui River Basin in Yang County,southern Shaanxi Province.The basin is located in a combination area of mountainous hills and basins with many tributaries.Affected by seasonal rainfall,the river soil is relatively loose and subject to lateral erosion by water flow,which may cause a risk of slope instability in the embankment sections on both sides of the river.In order to analyze the slope stability and safety of the embankments on both sides of the river after reinforcement and verify the effectiveness of reinforcement measures to eliminate risks,based on the characteristics of embankments in each region,two-dimensional finite element embankment models before and after reinforcement are established to analyze the influence of different factors such as river water level under the influence of seasonal rainfall,changes in embankment material properties and lateral erosion depth of the embankment foot on the stability and safety of embankment slopes.The results show that:when the water level rises,the embankment slope stability safety factor first increases,then decreases,and finally the slope becomes stable;when the water level drops,the embankment slope stability safety factor first decreases,then increases,and finally stabilizes.In addition,after the embankment is reinforced,the stability and safety of the embankment are significantly improved,and the reinforcement measures are effective.The research results have guiding significance for the design plan of risk reduction and reinforcement of shabby embankments.