降雨诱发堆积体浅层破坏特征及机理研究

Study on Shallow Destruction Characteristics and Mechanism of Rainfall-induced Accumulation Body

降雨诱发的堆积体滑坡广泛分布于三峡库区,通过研究此类滑坡的变形特征及失稳机制,分析其稳定性,对滑坡灾害的治理有重要意义。以桥头北次级滑坡为例,综合分析降雨、自动GNSS监测等数据,结合野外宏观巡查及勘查资料,研究了其变形特征及失稳机理。结果表明,桥头北次级滑坡整体变形明显,累积位移-时间关系曲线呈“阶跃”变形特征,降雨及因挡土墙排水失效导致的坡体饱和及地表漫流是诱发滑坡变形的主要因素,降雨通过孔隙和地表裂缝渗入坡体,地下水位抬升,积聚1~2 d后坡体饱和,变形加速开始,降雨结束3~7 d后恢复。

The accumulation landslides induced by rainfall are widely distributed in the Three Gorges reservoir area.By studying the deformation characteristics and instability mechanism of such landslides,the stability of such landslides is of great significance to the management of landslide disaster.This paper comprehensively analyzed the data of rainfall and automatic GNSS monitoring.Combined the field macro inspection and exploration data,the deformation characteristics and instability mechanism of landslide were studied.The results show that the overall deformation of Qiaotoubei secondary landslide is obvious,and the cumulative displacement-time relationship curve presents"step"deformation characteristics.The rainfall and retaining wall drainage failure of slope saturation and surface overflow are the main factor of landslide deformation.The rainfall permeates into slope through pores and surface cracks,and groundwater level rises.The slope saturation reaches after accumulation 1-2 d,the deformation begins to accelerate,and the rainfall recovers after 3-7 d.