宜宾岷江南岸半边街滑坡稳定性及敏感性评价

Stability and Sensitivity Evaluation of Banbianjie Landslide on the South Bank of Minjiang River in Yibin

以地处岷江南岸的宜宾市叙州区蕨溪镇半边街滑坡为研究对象,在滑坡工程地质勘查、岩土试验等基础上,对其特征、影响因素及变形机制等展开分析,并选取滑坡的两个主要剖面,利用极限平衡理论的传递系数法,对不同工况下的滑坡稳定性及暴雨工况下的敏感性因素进行定量分析。结果表明:滑坡变形在雨季、岷江河水下跌时尤为剧烈,持续暴雨及岷江河水快速涨跌为滑坡失稳的主要诱因;滑坡整体基本稳定,其中后部斜坡在暴雨工况下稳定性系数为0.991~1.026,处于不稳定-欠稳定状态,局部前缘斜坡在河水涨跌工况下稳定性系数为1.000,处于欠稳定状态,其他情况下均处于基本稳定-稳定状态;暴雨工况下黏聚力是影响滑坡稳定性的最主要敏感性因素。

Taking Banbianjie landslide in Juexi Town,Xuzhou District,Yibin City,which is located on the south bank of Minjiang River as the research object,the paper analyzed the characteristics,influencing factors and deformation mechanism of landslides on the basis of engineering geological exploration and geotechnical tests.It selected two main sections of landslide and used the transfer coefficient method of limit equilibrium theory to quantitatively analyze the landslide stability under different working conditions and the sensitive factors under rainstorm conditions.The outcomes show that a)the landslide deformation is especially severe in the rainy season and when the Minjiang River falls,and the continuous heavy rain and the rapid rise and fall of the river are the main causes of the landslide instability;b)the whole landslide is basically stable,and the stability coefficient of the rear slope is 0.991-1.026 under the condition of rainstorm and it is in the instability-understability state.The stability coefficient of the local front slope is 1.000 under the condition of river water fluctuation and it is in the understable state.In other cases,it is in the basically steady-stable state and;c)cohesion is the most sensitive factor affecting landslide stability under rainstorm condition.