三峡库区黄土坡滑坡库水位与降雨联合作用渗流应力耦合的数值模拟

Numerical Simulation on the Coupling of Seepage and Stress of Huangtupo Landslide with the effect Water Level Change and Rainfall in Three Gorges Reservoir Area

以三峡库区黄土坡滑坡为研究对象,通过野外调研与监测,利用FLAC有限差分软件建立了黄土坡滑坡在库水位与降雨联合作用下的渗流应力耦合数值分析模型,对不同工况下黄土坡滑坡的渗流应力耦合作用进行数值模拟分析,并探讨黄土坡滑坡的复活机理。结果表明:滑坡体前缘300m内受库水位的影响较大,坡体内的渗流应力耦合作用明显,在工况一及工况二下,由于库水位的下降使滑坡体内的地下水位线下降,并且伴随着大暴雨,滑坡体内的孔隙水开始向长江排泄,滑坡体出现明显的变形;在工况三及工况四下,由于库水位的上升使滑坡体内的地下水位线上升,并且随着降雨量的减小,滑坡体内出现了反向的渗流作用,加强了滑坡体的稳定性,使滑坡重新回到了相对稳定的状态。

Based on field investigation and monitoring data,this paper applies FLAC software to the establishment of a numerical simulation model to study the coupling of seepage and stress of Huangtupo landslide with the effect of water level changes and rainfall in Three Gorges Reservoir area, studies the coupling effect of seepage and stress of Huangtupo landslide under different working conditions and discusses the revival mechanism of Huangtupo landslide. The results show that,landslides within 300m of leading edge are greatly influenced by the water level, and the coupling effect of seepage and stress are obvious. Under condition 1 and condition 2, the decline of reservoir water level leads to the decline of the landslide phreatic line with the heavy rain,and pore water in landslide begin to drain to the Yangtze River with the heavy rain and meanwhile landslide shows obvious deformation. Under condition 3 and condition 4,the rise of reservoir water level leads to the rise of the landslide phreatic line,and landslide shows the effects of reverse seepage with the decrease of the rain,which strengthens the stability of the slope and restores the landslide to a relatively stable state.