摘要
以某厚堆积层滑坡为例,基于非饱和土力学理论,利用有限元方法,对雨水入渗条件下坡体的渗流及动态稳定性进行了计算和分析,研究了水分在坡体内的运移对边坡稳定性的时间效应。结果表明:边坡堆积体结构松散,土体强度差,边坡前缘坡降大,坡脚的开挖,为滑坡形成提供了便利条件;强降雨条件下使得坡脚附近首先发生变形失稳,牵引坡体后缘产生张拉裂。雨水沿坡面入渗,在坡体内形成渗流场,弱化岩土体参数,同时坡面形成饱和径流,使滑坡体前缘产生向下的渗透力,促使前缘坡体发生滑动,进而引发分级坡体产生滑移;强降雨初始阶段,滑坡体安全系数降低较快,很容易发生滑坡。该研究揭示了降雨入渗诱发厚堆积层边坡滑动机制,并以此建议采取以截、排、堵措施对边坡进行排水,同时设置嵌岩锚索抗滑桩及进行削坡清方措施对边坡进行综合治理,通过稳定性计算,效果良好。
Taking a certain thick accumulation landslide for example, and based on the theory of unsaturated soil mechanics, this paper uses the finite-element method to calculate and analyze the slope seepage and dynamic stability under the condition of rainfall infiltration and studies the time effect of water movement in the slope mass on the slope stability. The results show that the loose structure of the slope accumulation body, the poor soil strength, the large gradient at the slope front edge and excavation at the slope toe have provided a convenient condition for landslide formation. Under heavy rainfall, the deformation instability firstly occurred near the slope toe, and then pulled the slope rear edge and caused the tensile fissures. The rainwater infiltrated along the slope surface, formed the seepage field in the slope body and weakened the rock-soil mass parameters. Meanwhile, the saturated runoffs formed on the slope surface generated the downward seepage force on the slope front edge, and promoted the slope front edge to slide and triggered the slippage of the hierarchical slopes. In the initial stage of the heavy rainfall, the safety factor of the landslide mass reduced rapidly, which easily caused the landslide. This study reveals that the rainfall infiltration induced the sliding mechanism of the slope with thick accumulation horizon, based on which, the paper recommends to take the measures of water cut-off, drainage and water plugging to drain off the water, and to set the rock-socketed anchor cable anti-slide pile and taking the measures of slope cutting and cleanup earthwork to control the slope. Good effect results have been obtained through the stability calculation.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2013年第10期2898-2904,共7页
Rock and Soil Mechanics
基金
2012年度高等学校博士学科点专项科研基金资助课题(No.20120191110039)
干湿循环作用下岩石劣化宏细观损伤机制研究
关键词
非饱和
弱化
降雨
堆积体
机制
unsaturation weakening rainfall accumulation body mechanism
