软层对土质边坡破坏模式及稳定性影响的数值分析  

Numerical Analysis on Influence of Soft Layer on Failure Mode and Stability of Soil Slope

作　　者：孙婧 张志强[2] 李地元[1] 林杭[1] 朱泉企 SUN Jing;ZHANG Zhi-qiang;LI Di-yuan;LIN Hang;ZHU Quan-qi(School of Resources & Safety Engineering, Central South University, Changsha Hunan 410083, China;Institute of Geotechnical Engineering, Xi'an University of Technology, Xi’an Shaanxi 710048,China)

机构地区：[1]中南大学资源与安全工程学院,湖南长沙410083 [2]西安理工大学岩土工程研究所,陕西西安710048

出　　处：《公路交通科技》2019年第6期17-24,共8页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(51474250);中南大学研究生自主探索创新项目(2018zzts723)

摘　　要：为了研究软层对土质边坡破坏模式及其稳定性的影响,运用FLAC^3D建立多分层(坡体分4层,坡基分2层)土质边坡模型。将软层分为由内摩擦角φ控制的软层(内摩擦角φ较小的软层),以由黏聚力c控制的软层(黏聚力c较小的软层)。考虑工程实际选取4种常见的软层分布方式:①软层在边坡顶部、②软层在边坡底部、③软层在边坡顶部和底部、④软层在边坡中部,采用强度折减法分析了不同软层分布和不同软层性质边坡的滑动面和安全系数。结果表明:(1)内摩擦角φ控制的软层分布不同时,分布②边坡表现为圆弧+直线型破坏,其余分布则表现为圆弧型破坏;(2)黏聚力c控制的软层在不同分布时,分布②呈明显的圆弧型破坏,其余分布表现为一定程度的圆弧+直线型破坏;(3)位于边坡中部的软层显著降低其稳定性,其中以黏聚力c控制的软层不利影响最为显著;(4)随层间参数差异值的增大,不同的软层黏聚力c与内摩擦角φ对于滑动面上边缘距坡顶距离作用效果相反,而对于安全系数的影响表现一致;(5)针对软层位于边坡中部的情况,软层自身性质相较于其周围土层的性质对边坡稳定性影响更为显著。在相关施工中应主要对软层进行加固,并适当对其周围土层进行补强,可实现经济合理的支护方案。In order to study the impact of soft layer on failure mode andstability of soil slope, the model of multi-layer stratified soil slopewith body of 4 layers and base of 2 layers is simulated by FLAC^3D. Thesoft layer is divided into soft layer controlled by internal frictionangle φ(the soft layer with a smaller φ) and soft layer controlled bycohesion c(soft layer with a smaller c). Considering the engineeringpractice, 4 common soft layer distributions are chosen, including ①upper soft layer,②lower soft layer,③upper and lower soft layers, and④middle soft layer. The slip surfaces and safety factors of soil slopeswith different soft layer distributions and properties are analysed bystrength reduction method. The result shows that(1) for the soft layercontrolled by φ in different distributions, the slope of distribution② shows mixed failure mode of arc and beeline, and the rest of thedistributions are obviously arc failure modes;(2)for the soft layercontrolled by c in different distributions, the distribution ② isobviously arc failure mode, and the rest of the distributions show mixedfailure mode of arc and beeline to some extent;(3) the stability of thesoft layer in the middle part of slope is significantly reduced, and thesoft layer controlled by c is the most adverse;(4) with the increase ofthe difference of interlayer parameters, the effects of c and φ on thedistance between the upper edge of slip surface and the slope top areopposite, but their effects on the safety factor are the same;(5) forthe soil slope with soft layer in middle part, the property of the softlayer has more significant influence on the slope stability comparedwith that of the surrounding soil layer. In the construction, the softlayer should be mainly reinforced, and the surrounding soil layersshould be reinforced appropriately, so that an economical and reasonablesupport scheme can be realized.

关 键 词：道路工程 软层 数值模拟 破坏模式 稳定性 

分 类 号：TU43[建筑科学—岩土工程]