路堑边坡平面滑动演化过程及远程滑动机制的模拟与分析  

SIMULATION AND ANALISIS OF SLIDING EVOLUTION PROCESS AND LONG RUN-OUT SLIDING MECHANISM FOR PLANE SLIDING OF CUTTING SLOPE

作　　者：王浩[1] 孙木子[1] 马新凯 廖小平[1,2] 林一夫 吴志刚 

机构地区：[1]福州大学环境与资源学院资源与城乡建设系,福州350116 [2]中铁西北科学研究院有限公司福建分公司,福州350002

出　　处：《工程地质学报》2015年第3期438-447,共10页Journal of Engineering Geology

基　　金：国家自然科学基金(41002127);福建省自然科学基金(2013J01159);交通运输部建设科技项目(201331849A130);福建省交通科技项目(201242)资助

摘　　要：永宁高速公路K117滑坡路段原为在泥质粉砂岩单斜地层内开挖2级形成的路堑边坡,开挖后产生典型平面滑动,在中部滑床形成长约25m的滑动槽,产生最远达35m的远程滑距,其成因机制复杂。本文在对滑坡基本特征及孕育过程开展详细调查研究的基础上,采用节理有限单元法对该滑坡经路堑开挖导致高位坍滑、刷方变更后触发高速远程滑塌、滑塌后壁残留滑体牵引松动,以及对其实施卸载、支挡回填及锚固的治理过程开展数值模拟,再现了该滑坡孕育发展全过程及其稳定性演化规律;分析了该边坡破坏的平面滑动机构及滑动面的物理力学特征,论述了该类滑坡启动高速远程滑动的开挖松弛致滑机理和裂隙充水致滑机理,最后提出了预测及治理该类滑坡的6点建议。研究表明,在单斜地层开挖路堑,使顺倾向软弱结构面临空暴露时,可能诱发边坡整体卸荷松弛,产生较大的不平衡滑坡推力,而卸荷松动产生的张裂隙导致滑坡对降雨入渗十分敏感,不平衡力和裂隙水压力的共同作用可迅速剪断滑面,伴随势能向动能的转化,产生高速远程滑动。K117 landslide of Yong-Ning highway is a cutting slope with two excavation stages in argillaceous siltstone of monoclinic layer. The formation mechanism of this landslide is complex because it is the long run-out plane sliding as far as 35 m and the sliding pit as long as 25 m on slide bed when excavated. Based on the detailed investigation to its basic characteristics and development process,the landslide is simulated by joint finite element method in the process of its slide of three stages and landslide treatment. Firstly,the paper reappears the whole gestating process and stability evolving regulations of the landslide. It analyzes the plane sliding mechanism and thephysical and mechanical characteristics of sliding surface. Next,it discusses the long run-out sliding mechanism induced by excavating relaxation and filling water within fissure. Lastly,it proposes six suggestions to predict and control this landslide. The results shows that,when the weak structure planes in monoclinic layer is exposed on free surface after excavating,it can activate unloading relaxation of the whole slope and cause the great imbalance thrust of landslide. Meanwhile,landslide is very sensitive because of rainfall infiltration in stretched cracks. Due to change of potential energy to kinetic energy,sliding surface can be cut off rapidly by the interaction of imbalance thrust and fissure water pressure. Then it can be converted into high-speed and long run-out sliding.

关 键 词：路堑边坡 平面滑动 远程滑动 节理有限元法 强度折减法 

分 类 号：P641[天文地球—地质矿产勘探]