基于物理模拟实验的黑方台黄土滑坡破坏机理研究

Research on the failure mechanism of the Heifangtai loess landslides based on the physical simulation experiments

在黑方台地区,由于长年的灌溉引发了大量的黄土滑坡,以焦家4#滑坡为例,对该滑坡进行了近景摄影测量分析以及详细的野外调查工作,对黄土滑坡破坏机理进行研究。结果表明:黄土滑坡破坏前期后缘开始发育大量裂缝,破坏后后缘呈圈椅状,滑动面处于液态化的状态,滑体软弱松散,是该区危害最大的一类滑坡。建立物理模型模拟该滑坡的破坏过程,结果表明:该滑坡演化过程中,边坡中后部率先出现裂缝,逐渐向坡面发展,裂缝方向顺着斜坡坡面方向,最后贯穿滑坡体。边坡破坏时,孔隙水压力激增,导致黄土液化,强度降低,前缘塑性流出,边坡破坏;表面位移量达到最大,表明该滑坡具有明显的突发性特征。

In the Heifangtai area,there are many loess landslides for years of irrigation. The failure mechanism of loess landslides is examined base on the Jiaojia4# landslide. The close-range photogrammetry and detailed field investigation focusing on the deformation and failure of the Jiaojia4# landslide are carried out. The results of the analysis reveal that in the early stage of the loess landslides,many cracks occur in the rear of the landslides. After the loess landslides,the rear becomes a circle chair state,the slide surface is in a liquefaction state and the slide body is loose. Model tests are the most commonly ways to obtain the failure mechanism of landslides. The model test reveals that during the loess landslide,cracks first occur in the middle and rear,and they develop to the hillslope till throughout the slide body. When failure occurs,on the one hand,the pore-water pressure increases sharply,which lead to the liquefaction of loess,causing the reduction of strength and the outflow of the front of the landslide. On the other hand,the displacement of the surface reaches the maximum,indicating that the loess landslides occur with a sudden. The research has a guiding significance to the forecast and prevention of loess landslides.