库水位波动条件下不同桩位抗滑桩抗滑稳定性研究

水库滑坡抗滑桩治理设计工作中,桩位的合理选择直接关系到工程安全和造价。以张桓候庙园区东侧滑坡为例,在分析滑坡地质条件的基础上,依据三峡水库实际运行条件进行不同桩位滑坡变形规律及稳定性变化规律的GeoStudio数值模拟研究。结果表明:①库水位上升时,滑坡前缘位移减小,后缘位移增大。滑坡前缘在水位下降和最低水位时出现位移极大值;滑坡后缘在水位上升和最高水位时出现位移极大值。②对滑坡后缘位移最有效的控制桩位为位于地面高程175 m的下滑段接近滑坡最大推力区域的桩位Ⅰ,对前缘和中部位移最有效的控制桩位是位于距滑坡剪出口130 m阻滑段的桩位Ⅱ,最优桩位是桩位Ⅱ。考虑水位波动的影响,提出了对现有抗滑桩设计的设计安全系数修正方法,为水库滑坡抗滑桩设计提供参考。

Anti-sliding stability of different pile positions under reservoir water level fluctuation

In anti-sliding pile designing for Reservoir landslide improvement, the reasonable pile position determination is very important, which effects the engineering safety and cost. Taking Zhanghuanhoumiao east landslide for example, based on the engineering geological condition investigation and with the GeoStudio software, according to the reservoir operation curve, considering 4 different pile positions, the numerical simulations were done. The results show that: ① When water level rising up, the displacement of front edge decreases, but the displacement of back edge increases. The maximum displacement of the front edge appears during water level drawing down and lowest water level. The maximum. displacement of the back edge appears during water level rising up and the highest water level. ② The reasonable pile position for the back, front and middle of the landslide are separately Ⅰ, Ⅱ pile positions. I pile is at the 175m, which residual pushing force is maximum the best pile is Ⅱ pile position, which is 130m from the shearing out point of landslide. At last, considering the influence of the water level fluctuation, the modified method of the safety factor for the anti-sliding pile design is presented, which will be important to the anti-sliding pile design for reservoir landslide.