窑洞开挖诱发浅层黄土滑坡的变形机理模拟

Numerical simulation on the deformation mechanism of shallow loess landslides induced by deserted cave dwellings

由废弃窑洞倒塌引发的黄土边坡失稳严重威胁了黄土高原地区居民的生命财产安全。通过野外调查,选取陕西省延安市三亩台滑坡为典型案例,基于室内试验分析了窑洞废弃、依窑建房等工况下黄土含水量和土体强度的变化规律,运用数值模拟研究了窑洞废弃、依窑建房过程中最危险滑面上的应力和强度变化趋势。从土体应力-强度关系角度揭示了废弃窑洞诱发黄土边坡变形破坏机理。研究表明,窑洞废弃和依窑建房增大了土体含水量,降低了土体的抗剪强度,致使坡体下部土体剪应力逐渐接近其抗剪强度,边坡的稳定性随之降低,最终窑洞坍塌引发滑坡。

There are lots of landslides triggered by deserted cave dwellings that threaten people＇s life and property safety in the loess area, With Sanmntai landslide in Yan＇an as a study case, the authors detected the variation regularity of moisture content and strength of loess during the deserting of cave dwellings and the building of houses beside the cave dwellings through laboratory test. The stress and strength change on the most dangerous slip surface were studied and the mechanical mechanism of the development of deformation and the failure of loess landslide were revealed. The results show that the deserting of cave dwellings and the building of houses beside the cave dwellings would increase soil moisture content and reduce soil strength, making it nearly impossible for the stress distribution in the lower part of the slope to resist the shear stress and thus causing the collapse of cave dwelling and the occurrence of landslides.