侵蚀作用诱发黄土滑坡的机制研究

侵蚀作用诱发的黄土滑坡是黄土高原区域内一种主要的滑坡类型，对其破坏机制开展深入研究具有重要实际意义。以陕西省耀州区的庵里滑坡为例，对该类黄土滑坡的发生机制进行分析和探讨，建立了滑坡发生前侵蚀作用的不同阶段边坡的有限元模型，计算了相应的应力场和位移场，在此基础上求得各模型沿最终滑面上的正应力、剪应力和抗剪强度分布，采用极限平衡法计算边坡整体稳定系数。结果表明，随着侵蚀作用的不断加深，沿滑动面上的剪应力增大，抗剪强度减小，整体稳定性降低至最终破坏。试验结果表明，小的应变在饱和黄土中会产生显著的超孔隙水压力，因此，基岩面上饱和滑带中的超孔隙水压力加剧了该类滑坡的发生。比较滑面上的剪应力和抗剪强度发现，自前滑坡破坏从坡脚开始，向后逐步扩展，表明该类滑坡具有牵引式破坏特点。

Research on mechanism of loess landslides caused by erosion

The erosion-induced loess landslide is a typical landslide in the Loess Plateau.It has important practical significance to do some research on its mechanism.Taking Anli landslide in Yaozhou district,Shaanxi province as example,this paper discusses its initiation mechanism,establishes finite element models at different stage caused by headward erosion before sliding through finite element method,and calculates the stress and strain fields in each stage.On this basis,the shear stress,normal stress and shear strength on the final sliding surface in every model are obtained.The stability factors are also acquired by limit equilibrium method.The result shows that,with the deepening headword erosion,the shear stress on sliding surface increases constantly;but the shear strength decreases conversely.The stability of the whole landslide never reduced until failure.The experimental result shows that,the low-strain can produce a significant excess pore water pressure in saturated loess.Therefore,the excess pore water pressure in saturated sliding zone fosters the failure of this landslide.Comparing the shear stress and the shear strength,the erosion-induced landslide has a failure from the foot to the back part gradually.Therefore,this kind of landslides has characteristics of traction damage.