堆积层滑坡在库水位变动与降雨共同作用下的阈值研究——以墓坪滑坡为例

Study on the Threshold Value of Colluvial Landslide under the Combined Action of Reservoir Water Level Variation and Rainfall:Taking Muping Landslide as an Example

堆积层滑坡是三峡水库运行过程中的重要地质灾害,其变形演化往往受库水位变动与降雨强度的影响,如何确定库水位与降雨共同作用下的合理有效阈值判据,准确为滑坡防范与应急处置提供及时可靠的信息成为当务之急。以堆积层滑坡——墓坪滑坡为例,基于实时监测数据,并结合数值模拟方法,对库水位变动与降雨强度下的阈值进行研究。结果表明,当库水位下降速率为0.11~<0.42 m/d、4~10 d累积降雨量≥57.3 mm时,墓坪滑坡易发生变形;当库水位下降速率为0.42~<0.83 m/d、4~10 d累积降雨量≥45.8 mm时,墓坪滑坡易发生变形;当库水位下降速率≥0.83 m/d、4~10 d累积降雨量≥22.3 mm时,墓坪滑坡易发生变形。通过数值模拟分析,当库水位下降速率≥0.4 m/d、且连续3 d累积降雨量≥100 mm时,墓坪滑坡易发生变形。研究成果可以为墓坪滑坡的监测预警预报工作提供依据,对涉水堆积层滑坡监测预警也有一定的借鉴。

Colluvial landslide is an important geological disaster during the operation of the Three Gorges Reservoir,and its deformation evolution is often affected by the variation of reservoir water level and rainfall intensity.How to determine the reasonable and effective threshold criterion under the joint action of reservoir water level and rainfall,and provide timely and reliable information for landslide prevention and emergency treatment is an urgent task.Taking the accumulation landslide-Muping landslide as an example,based on the real-time monitoring data and combined with the numerical simulation method,the threshold of reservoir water level change and rainfall intensity is studied.According to data analysis,the rate of reservoir water level decline is greater than or equal to 0.11 m/d and less than 0.42 m/d,4~10 d the accumulated rainfall is greater than or equal to 57.3 mm,Muping landslide is prone to deformation.When the decline rate of reservoir water level is greater than 0.42 m/d and less than 0.83 m/d,4~10 d the accumulated rainfall≥45.8 mm,Muping landslide is prone to deformation.When the reservoir water level drop rate≥0.83 m/d and 4~10 d the accumulated rainfall≥22.3 mm,Muping landslide is prone to deformation.Through numerical simulation analysis,when the reservoir water level drop rate≥0.4 m/d,and the cumulative rainfall for three consecutive days≥100 mm,Muping landslide is prone to deformation.The research results can provide a basis for the monitoring,early warning and forecasting of the Muping landslide,and also have some reference for the monitoring and early warning of the wading accumulation landslide.