Abstract: Taking Nanwan landslide in Southwest Henan Province as an engineering example, combined with soil mechanics seepage theory and FLAC^3D software, three-dimensional numerical simulation of Nanwan landslide in southwest Henan Province was carried out by using finite difference software FLAC^3D software through the influence of reservoir water level sudden drop on pore water pressure and seepage field distribution, combined with two-dimensional unsaturated seepage theory and two-dimensional seepage analysis software in soil mechanics. The results show that the pore water pressure of the soil mass in Nanwan landslide in southwest Henan Province tends to increase when the reservoir water level was at 105.89m, and the soil mass was relatively dense, which has no adverse effect on the stability of the landslide. When the reservoir water level drops abruptly, the pore water pressure of the landslide body drops rapidly, driving the flow of soil particles in the landslide body. Due to the change of seepage force, the safety factor of landslide soil mass was reduced, and then the local instability of landslide soil mass was caused. It provides a theoretical reference for the analysis and evaluation of landslide stability under the state of reservoir water level rise and fall.

Key words: landslide, rise and fall of reservoir water level, FLAC^3D software, three-dimensional numerical simulation

摘要： 文中以豫西南南湾滑坡为工程实例,结合土力学中二维非饱和渗流理论和二维渗流分析软件,通过库水位突降对孔隙水压力和渗流场分布的影响,采用有限差分软件FLAC^3D软件对豫西南南湾滑坡进行三维数值模拟,计算三维状态下滑坡的应力和位移场特征。结果表明:豫西南南湾滑坡土体孔隙水压力在库水位处于105.89m时,水压力有增大趋势,土体较为密实,对滑坡体的稳定性没有产生不利影响;当库水位突降后,滑坡体孔隙水压力迅速下降,带动滑坡体内的土颗粒流动,由于渗流力的变化,使得滑坡土体的安全系数降低,进而产生滑坡土体局部失稳破坏。该研究为分析评价库水位升降状态下滑坡的稳定性分析提供理论参考。

关键词: 滑坡, 库水位升降, FLAC^3D软件, 三维数值模拟