鄱阳湖区洪水全过程下堤防稳定性有限元模拟计算分析

Analysis on stability of embankment in Poyang Lake Area under whole process of flood based on finite element method simulation

为研究2020年超历史大洪水情况下鄱阳湖区堤防的边坡稳定性,基于堤身材料二元分布特征,采用有限元方法模拟了堤防在水位上升期、持续高水位期及水位降落期全过程的孔隙水压力与安全系数变化,并考虑降雨强度与降雨历时等不利因素的影响,分析了堤防在洪水全过程作用下的边坡稳定性。结果表明:水位变化速率对最终孔压及上下游坡的安全系数无影响;降雨会显著提高堤身孔隙水压力、降低上下游坡安全系数,易使堤防出现管涌、渗漏及滑坡等险情,因此应对堤防进行洪水全过程的安全巡查。研究成果可为堤防防汛抢险提供参考。

In order to study the slope stability of embankments in Poyang Lake area under the super-historical flood in 2020,according to the two-variable distribution characteristics,the finite element method was used to simulate the whole process changes of pore pressure and safety factors of embankments in the water level rising period,continuous high water level period and water level falling period.Considering the influence of different rainfall intensities and rainfall duration conditions on the seepage field,the stability of embankments under the coupling effect of water level and rainfall were analyzed.The results showed that the change rate of water level had no effect on the final pore pressure and the safety factor of upstream and downstream slopes.Rainfall significantly increased the pore pressure of the embankment and reduced the safety factor of upstream and downstream slopes,which was easy to cause piping,leakage and landslide of the embankment.Therefore,the inspection of the whole flood process should be strengthened.The research results could provide a reference for flood control of embankments.