基于数值流形法的反倾层状岩质边坡倾倒破坏模拟

倾倒变形破坏是岩质边坡的一种典型破坏失稳形式,为研究重力作用下反倾层状岩质边坡在不同岩层倾角下的破坏特征,使用石根华博士提出的二维数值流形法(NMM),以青藏高原金沙江流域的西藏昌都地区芒康县索多西乡贡扎倾倒滑坡为研究案例,依据实地考察数据建立数值计算模型,模拟反倾岩质边坡的倾倒破坏过程。研究表明:岩层倾角小于45°时,反倾斜坡的变形破坏是从边坡中部倾倒区域开始的,倾倒区的破坏使得上部的稳定区岩石逐级发生破坏成为倾倒区的主体,从而提供了巨大的下滑力推动下部岩体发生滑移,使得整个斜坡发生倾倒破坏;当岩层倾角大于45°时,边坡的变形是由边坡下部逐渐向上部坡顶发展,且边坡上部也会出现明显的弯曲变形,呈“点头哈腰”式变形破坏。

Toppling Failure Simulation of Anti-dipping Layered Rock Slope Based on Numerical Manifold Method

Toppling deformation failure is a typical failure and instability form of rock slopes.In order to study the failure characteristics of anti-dipping layered rock slopes with different rock dip angles under the action of gravity,we took Gongzha landslide in Soduoxi Town,Mangkang County,Changdu Prefecture of Tibet as an example,adopted the two-dimensional numerical manifold method(NMM)to simulate the toppling failure process of the anti-dipping rock slope based on the numerical calculation model established on fieldwork data.As the results show,when the dip angle of rock stratum is less than 45°,the deformation failure of the anti-dipping rock slope starts from the dumping area in the middle of the slope,and the failure of the dumping area makes the rock in the upper stable area gradually fail and becomes the main body of the dumping area,thus providing a huge sliding force to push the lower rock mass to slide and causing the whole slope to topple.When the dip angle is greater than 45°,the deformation of the slope develops gradually from the lower part of the slope to the upper slope,and the upper part of the slope will show an obvious bending deformation in the shape of“nodding and bowing”.