顺层岩质滑坡变形破裂扩展及高速失稳特征研究——以四川省“5·5”三河口顺层滑坡为例

Study on deformation fracture and high speed movement characteristics of consequent rock landslide:case of"5·5"Sanhekou landslide in Sichuan Province

2018年5月5日,四川乐山市三河口乡发生高速岩质滑坡,方量约23.4万m^3,滑坡自启动至堆积过程影像记录清晰。基于现场勘探和无人机航空摄影,对滑坡发育的形貌特征、结构特征、运动及堆积过程进行了调查,对滑坡的变形破裂扩展、形成机理进行了分析。研究表明:斜坡侧缘和后缘节理对滑坡启动起到主控作用,滑坡主滑用时16 s,最大水平运动距离约215 m,最大运动速度约24.1 m/s;斜坡在重力作用下沿层面发生蠕变,随着变形累积,周缘节理破裂逐渐贯通、掉块,侧缘的渐进贯通对最终破坏起到控制作用。该滑坡运动和破坏模式较为典型,研究成果对其他类似顺层岩质斜坡失稳机理研究具有借鉴意义。

On May 5,2018,the rock landslide occurred in Sanhekou Township,Mabian County,with a volume of about 234000 m^3.The image records of the landslide from start-up to accumulation were clear.Based on field investigation and aerial photography,this paper investigated the morphological characteristics,rock mass structure,movement and accumulation process of the landslide development,and analyzed the formation mechanism of the landslide.The research showed that the lateral and rear edges played an important role in the stability of the slope,the major sliding duration of the landslide was 16 s,the horizontal movement distance was about 215 m,and the maximum speed was about 24.1 m/s.The slope crept along the bedding under gravity.The fracture of the circumferential joint was gradually penetrating accompanied with falling blocks in the accumulated deformation process,and penetration of the lateral edge controlled the final failure.The motion and failure modes of the landslide are typical,which can be used for reference to study the failure mechanism of consequent rock slopes.