复杂应力状态下土质高边坡稳定性分析

结合现有的实际滑坡场地,开展了关中盆地黄土塬边的高边坡稳定性研究。基于弹塑性理论和非关联流动法则,根据双剪统一强度理论,建立了双剪统一弹塑性本构模型的显式有限差分格式。针对陕西省泾阳县南塬高边坡滑坡的现场勘测和室内试验,分析了滑坡的规模和滑坡前后的地形特征。在此基础上,还原了滑坡前的边坡地形概状,建立三维计算模型并运用三维拉格朗日有限差分方法分析了中间主应力对高边坡稳定性的影响;然后考虑中间主应力的影响对不同地下水埋深和渗流时边坡的稳定性进行分析。结果表明,考虑中间主应力情况下,随着地下水位升高,坡顶水平向位移增大;当不考虑渗流时,坡顶水平位移增大到一定值后边坡达到稳定状态,而考虑渗流时坡顶水平位移持续增大,并且容易发生突然的破坏失稳。期望对泾阳南塬滑坡群的破坏机制研究提供一定参考。

Stability analysis of high soil slope under complex stress state

Based on the existing landslide field, a stability analysis of high slope along the loess plateau of Guanzhong Basin is presented. The format of explicit finite difference of twin shear unified elastoplastic constitutive model is developed which is based on the elastoplastic theory, non-associated flow rule and twin shear unified strength theory. According to the site surveys and laboratory tests, the terrain features before and after sliding and scale of the slope are analyzed; and the three-dimensional model is created from the sketch of terrain before the landslide event. With the influence of intermediate principal stress, stability analysis of high slope is processed with FLAC3D; ground water level variation and seepage flow are taken into account. The results show that the horizontal displacement at top of slope increases with the rising of ground water level with the consideration of intermediate principal stress. The result of no seepage flow calculation shows that the slope reaches a steady state under a certain displacement yielded on the top of slope. However, the displacement increases continually and then sudden failure may occur when the seepage flow is taken into account. This study may provide a reference for the research of failure mechanism of high soil slope.