宜巴高速公路香溪河库区某滑坡渗流及稳定性分析

根据三峡库区库水位调控方案,对宜昌-巴东高速公路三峡库区香溪河段某滑坡进行稳定性分析.采用有限元程序模拟该滑坡在库水位涨落条件下的非稳定渗流场变化过程,得到了库区不同蓄水速率和消落速率边界条件下滑坡内孔隙水压力和浸润线的分布规律;基于渗流计算结果,并利用摩根斯坦-普赖斯极限平衡法分析了对应边界和工况条件下滑坡稳定性系数变化.研究结果表明:由于该滑坡前缘涉水体积小,渗流场受库水涨落幅度和速率影响小,以致滑坡稳定性变化幅度不大,总体变化波动为1.2%～1.7%;库水涨落过程中的稳定性系数均呈现出先递减然后递增的V形变化趋势;而且蓄水和消落速率越大,滑坡稳定性减小的幅度和速率越大,表明库水涨落速率是控制库岸滑坡稳定性的主要因素之一.

Analysis of the seepage and the stability of a landslide at Yi-Ba Highway in Xiangxihe Reservoir

In term of reservoir regulation scheme of Three Gorges,the stability analysis of a landslide developed in Xiangxi River reservoir at a site of Yi-Ba highway is carried out.Utilizing FEM numerical program,the process of transient seepage field’s changes is simulated,and the spatial distributions of pore water pressure and location of phreatic surface under different boundary conditions including different filling rate and sluicing rate are obtained.Based on the seepage results,the regulations of stability change under correspondent boundaries are analyzed using Morgenstern-Price limit equilibrium method.The analysis reveals that seepage field in this landslide is subject to a little affection of reservoir water level due to a few front part involved immersion in water,which results in the change of stability by 1.2%~1.7%.During the process of filling and sluicing of reservoir,the factor of stabilities decreases at first,then increases.The greater of filling rate and sluicing rate,the bigger and prompter of the decrease of the stability.The results show that the rate of filling and sluicing plays an important role on the change of the stability for reservoir landslide.