库水位下降诱发的特大型顺层岩质滑坡变形特征与诱发机制

通过三峡库区旧县坪滑坡2016年6月?2018年8月的GNSS监测数据,采取多因素综合过程分析和定量分析手段,分析了滑坡变形在库水位7个不同变化过程下的响应特征和诱发机制.研究表明:(1)库水位下降是旧县坪滑坡位移变形的主要诱发因素,一般情况下,库水位下降速率越大,滑坡稳定性越差:库水位快速下降期间(＞0.4 m/d)...

Deformation characteristics and inducing mechanisms of a super-large bedding rock landslide triggered by reservoir water leve l decline in Three Gorges Reservoir area

Based on the GNSS monitoring data of Jiuxianping landslide in the Three Gorges Reservoir area from June 2016 to August 2018,comprehensive multi-factor dynamic process analysis and quantitative analysis are performed to analyze the response characteristics and the inducing mechanisms of landslide deformation under seven different changing processes of reservoir water level(RWL). The research results show that the falling of the RWL is the main inducing factor for the deformation of Jiuxianping landslide. In general,the greater the rate of the RWL decline,the worse the stability of the landslide. Landslide deformation can be promoted by intense rainfall including short-term heavy rainfall,continuous heavy rainfall and intermittent heavy rainfall during the falling period and the 145 m maintaining period of RWL,while it can hardly be promoted by any type of intense rainfall in the RWL rapid rising period(>0.5 m/d). For inducing landslide deformation,heavy rainfall can compensate with the RWL decline rate. In other words,generally speaking,the greater the RWL decline rate,the smaller the threshold of the precipitation which could induce the landslide deformation. That is to say,for a reservoir wading landslide,the rainfall threshold is not fixed but varies greatly with the process of the RWL change. As the direction of the seepage pressure points into the inside of the slope during the RWL rising-falling transition period,neither of the intense rainfall nor the RWL falling rate can induce the landslide deformation for about a few days to more than ten days. During the period of high frequency and low amplitude fluctuations of the RWL,the direction of the total seepage pressure generally points into the inside of the slope,therefore,the apparent landslide deformation cannot be induced by the RWL decline in this period. These research results are meaningful for the deformation inducing mechanism analysis,dynamic risk management,emergency treatment,and early warning criteria of monitoring for the reservoir wading landslide.