库水位波动条件下黄土坡临江1~#崩滑堆积体稳定性研究

Study of stability of Huangtupo riverside slumping mass #1 under reservoir water level fluctuations

水库蓄水是诱发三峡地区库岸滑坡的主要因素之一,开展库水位波动条件下滑坡稳定性研究意义重大。通过现场地质调查、原位监测、理论分析和数值模拟等手段,对三峡库区黄土坡临江1~#崩滑堆积体在库水位波动条件下的稳定性进行了研究。利用现场监测数据,分析了滑坡体地下水位与库区水位的关系、滑坡体深部不同高程处位移随时间的变化值以及库水位波动对滑坡体变形的影响。采用三维离散元程序"3DDEC",对临江1~#崩滑堆积体进行了数值模拟,分析了库水位波动条件下滑坡体内应力、应变的变化规律,并提出了考虑干湿循环作用的强度折减法,定义了安全系数的求解方法。研究结果表明,三维离散元法结合强度折减法研究水库滑坡是可行的;黄土坡临江1~#崩滑堆积体在目前的调水曲线作用下处于稳定状态;由2013年12月16日巴东地震前后滑坡堆积体的变形可现低烈度地震对滑坡体的稳定性影响不大。

Because reservoir water is one of the master factor inducing slope landslide in the Three Gorges area, it is significant to study the stability of landslide under the condition of water level fluctuation of reservoirs. We make a study of the stability of Huangtupo riverside slumping mass #1 in Three Gorges area under the condition of water level fluctuation of reservoirs by the measure of geologic survey and in situ monitoring and theoretical analysis as well as numerical simulation. We make a study of the relationship between reservoir water level and the landslide groundwater level in the place mentioned above based on the analysis of field monitoring data. And we also analyze the deep displacement changed over time at different altitudes of the landslide as well as the influence of the variation of water level of reservoirs on the deformation of landslide via the same data. We make a simulation of landslide mentioned above through '3DDEC' and analyze the changeable rule of stress-strain of landslide under the variation of water level of reservoirs; and we put forward the strength reduction method considering the action of drying-wetting cycle and define the method to solve the safety factor. The results show that: it is reasonable adopting '3DDEC' to anlyze sliding slope; Huangtupo riverside slumping mass #1 is in a stable state under the action of current water transfer curve; in particular, we find that the low seismic intensity has little effect on the stability of the landslide based on the analysis of the deformation of the slumping mass before and after the Badong earthquake in December 16, 2013.