长江科学院院报2019，Vol.36Issue(12)：126-132,7.DOI:10.11988/ckyyb.20180678
黄土-砂岩二元结构路堑高边坡失稳机制模拟分析
Simulation and Analysis of Instability Mechanism of High Cutting Slope with Loess-Sandstone Dual Structure
摘要
Abstract
A large number of typical dual-structured slopes with loess layer on the upper part and sandstone layer on the lower part are encountered in cutting excavation projects in northwest China with complex geological back-ground. To determine the instability deformation mechanism of such high cutting slope, we built a finite element model for the entire excavation process of the dual structure using GEO-studio with segment K35+092 along the ex-pressway from Lanzhou to Yongjing as research background. The damage characteristics and failure mechanism of loess-sandstone dual structure slope were investigated systematically in terms of the horizontal and vertical displace-ment and the change of safety factor during staged excavation unloading, as well as the stress and strain of slope in excavation state. The results indicate that the instability and deformation mechanism of loess-sandstone dual-struc-tured high cutting slope is determined by structural characteristics formation lithology. Under the action of excava-tion disturbance, the displacement of slope crest increased, the plastic strain in soil accumulated, and the steady state of the slope gradually weakened. The weak interlayer in the high cutting slope acts as sliding cushion which plays the role of lubrication and weakening the boundary, thus is a potential destabilizing factor of the slope. With the unloading of the slope, the upper part of the slope, namely, loess, slips and damages the lower slope body; in turn the joint action caused by the shear failure of the lower part caused the slumping of the upper part, resulting in an overall instability of the slope. In order to avoid instability and collapse of similar high cutting slope with dual structures, we put forward some corresponding reinforcement recommendations.关键词
路堑高边坡/二元结构/失稳破坏机制/有限元模拟/安全系数Key words
high cutting slope/dual structure/failure mechanism of instability/finite element simulation/safety fac-tor分类
交通工程引用本文复制引用
叶帅华,赵壮福,时轶磊..黄土-砂岩二元结构路堑高边坡失稳机制模拟分析[J].长江科学院院报,2019,36(12):126-132,7.基金项目
国家自然科学基金项目(51508256,51768040) （51508256,51768040）
甘肃省建设科技攻关计划项目(JK2015-5) （JK2015-5）
兰州市科技发展计划项目(2015-3-131)) （2015-3-131）
