降雨条件下楼房山隧道碎石土边坡的稳定性研究

通过建立楼房山隧道罐子沟端滑坡防治工程数值计算模型,研究降雨对碎石土边坡稳定性的影响机制,将降雨条件转化为含水率的变化,分析了不同含水率变化下边坡的应力场、位移场、塑性区及剪应变增量的变化规律。研究结果表明:在降雨条件下,碎石土边坡的稳定性随着含水率的增加呈先缓慢减小后急剧减小的特征,即存在一个与含水率有关的临界特性;降雨诱发碎石土边坡失稳的主要机理是雨水渗入后在地下水管道排泄系统作用下,将坡体下部碎石土中的细粒土带走,逐渐形成坍塌滑移,导致整个边坡破坏。

Study on Stability of Gravel Soil Slope along Loufangshan Tunnel during Rainfall

With the numerical calculation model for landslide control engineering at the end of Guanzi Gully of Loufangshan Tunnel, the mechanism how rainfall affects stability of gravel soil slope was studied to the extent that, by converting rainfall condition into variation of water content, the change rules of the stress field, displacement field, plastic zone and shear strain increment in the slope under different water contents were analyzed. The results show that, on the condition of rainfall, the stability of gravel soil slope is characterized by first slow then rapid decrease as the water content increases, that is to say, there exists a critical feature related to water content; and the main mechanism of the slope failure induced by rainfall is that, after rain water infiltrates, the fine grained soil in the gravel soil at the lower part of the slope will be brought away under the action of groundwater eduction piping system, gradually forming slump, then the slope failure as a whole.