甘肃舟曲垭豁口滑坡复活机理及成因探讨

2019年7月19日18时许，甘肃舟曲县垭豁口滑坡复活，约3.92×106 m3的滑体顺坡而下，迅速流入岷江，堵塞河道，造成河道水位上升，江边公路中断，滑坡变形持续至8月中旬。基于野外勘察、遥感解译、钻孔勘探等方法获取了滑坡变形的基本特征，并开展了滑坡监测工作，并结合气象资料，探讨了该滑坡复活原因及启动机制。初步研究认为，该滑坡为降雨诱发。通过对滑坡变形历史进行梳理，结合滑带证据，滑坡复活机理可概括为:首先上部块体缓慢蠕变，降雨后发生塑性流滑；其次，因上部滑体堆积在滑坡中部，造成中部平台堆载，引发中部滑体变形；最终一滑而下，刮产连带下部滑体坠入河道。滑坡的上中下三部分滑体逐步被激活，最初缓慢变形，随后加速启动。滑坡变形模式为蠕滑—拉裂—流滑。对滑坡变形过程和机理的初步判断为滑坡灾害应急处置提供了科学依据。

Mechanism and causal analysis on the Yahuokou landslide reactivation and causes(Zhouqu County,Gansu, China)

The report described a recent landslide happened in Zhouqu Country,China.At 18:00 pm Beijing time,on July 19,2019,the Yahuokou landslide was reactivated,about 3.92×10⁶ m³ of debris slumped from the slope caused Minjiang River channel blockage,water level rise,and road interruption.Fortunately,nobody was injured.In order to seek the geomorphologic and stratigraphic characteristics,the reactivated causes and the dynamics mechanism of the landslide,field survey,remote sensing image,drilling prospecting,landslide monitoring and rainfall data analysis were conducted.The outlook of the landslide event was given.Evidences of the sliding zone indicated the landslide is a flow-slide deformation pattern.The landslide mechanism is summarized as:firstly,slow plastic flow-slide occurred in the upper sliding body.Then the platform in the middle gentle slope was preloaded by the post upper part failure deposits,resulting in the"cutting and filling"effect.The failure form is creep-tension cracks-debris flow-slide.At last,the block on the lower part slumped.Specifically,the upper,middle and lower parts of the landslide all transferred stress in this mode,being activated step by step,and slowly slumped into the river.