库水位降落对V形冲沟超高多层路堤稳定的影响研究

Research on Influence of Reservoir Water Level Decrease on Stability of Super-high and Multi-layer Embankment over V-shaped Gully

V形冲沟超高路堤的稳定性受到库水周期性起落的影响。选取横穿三峡库区V形冲沟的超高多层路堤作为研究对象,借助FLAC两相流渗流计算功能,选择不同的降落水位,实现流-固耦合计算,重点分析路堤土体饱和度与孔隙水压力、水平位移与最大剪应变增量的变化规律,得到了三种工况下路堤稳定系数随库水位降落的变化关系。结果表明:库水位每当下落1 m,超高多层路堤稳定系数平均减少1.2%左右;库水位回落到最低水位145 m时,路基的稳定性最差。

The seasonal fluctuation of reservoir water level has impact on the stability of super-high embankment over V-shaped gully. The super-high and multi-layer embankment over V-shaped gully of the Three Gorges Reservoir was selected as a research object. Based on the two-phase flow option in FLAC,different water drop levels were selected to realize fluid-solid coupling calculation,and the variation law of embankment soil saturation,pore water pressure,horizontal displacement and maximal shear strain increment was mainly analyzed to get the relationship between embankment＇s safety factors and different water levels of reservoir under three work conditions. The results showed that the embankment＇s safety factor drops about1. 2 % where the water level goes down at the rate of one meter. The embankment is most instable at 145 m in water level.