库水位降速对缓倾角堆积层滑坡稳定性的影响

Influence of declining rate of reservoir water level on the stability of gently inclined colluvial landslide

缓倾角堆积层滑坡为库区常见的地质灾害类型,其常表现为体积规模大、物质成分复杂,滑坡变形呈现周期性和长期性。库水位下降常是诱发该类滑坡变形破坏的重要因素,因此研究库水位下降速率对缓倾角堆积层滑坡稳定性的影响具有重要意义。以缓倾角堆积层滑坡——贵州何家坪子滑坡为例,研究不同库水位下降速度(0.5、0.7、0.9、1.1、1.3 m/d)条件下滑坡不同滑体物质结构对库水位下降速度的响应差异。结果表明:不同库水位下降速度条件下,滑坡不同部位的稳定性均表现出先下降后上升的变化趋势,并且随着库水位下降速度的增大滑坡稳定性系数的下降幅度也增大;滑体渗透性弱的区域变形比滑体渗透性强的区域大;模拟结果与现场监测数据吻合,滑坡稳定性对于库水位下降速度的响应呈现明显的空间差异性。在缓倾角堆积层滑坡的风险防控中,应充分考虑库水位调节速度、滑体物质结构与滑坡变形的关系。

Gently inclined colluvial landslide is a common type of geological hazard in the reservoir area. It is often characterized by large volume, complex material composition, and periodic and long-term deformation.The declining of reservoir water level is often an important factor inducing the deformation and failure of such landslide.Therefore, it is of great significance to study the influence of the declining rate of reservoir water level on the stability of gently inclined colluvial landslide.In this paper, Hejiapingzi landslide in Guizhou Province as a gently inclined colluvial landslide is taken as an example to study the stability response of different landslide material under different declining rates(0.5,0.7,0.9,1.1 and 1.3 m/d) of reservoir water level.Under different declining rates of reservoir water level, different landslide parts show that the stability firstly decreases and then increases, and the stability coefficient of the landslide declines with the increase of the declining rate.The deformation of the landslide area with weak permeability is greater than that in the area with strong permeability.The simulation results are consistent with the on-site monitoring data, and the response of landslide stability to the declining rate of reservoir water level shows obvious spatial differences.In the risk prevention and control of gently inclined colluvial landslide, the relationship between the declining rate of reservoir water level, the landslide material and the landslide defor-mation should be fully considered.