摘要
为阐释山区公路刚性挡土墙拓宽加筋路基稳定性的动态演变规律及机理,结合山区公路路基拓宽改建多外设刚性挡土墙的特殊性,运用Phase^2有限元软件,考虑土-结构相互作用,建立数值模型,所获加筋效果相关结论经离心模型试验宏观验证,开展基于剪切强度折减法的山区公路拓宽加筋路基稳定性分析,探究填土、土工格栅和填土-土工格栅界面三者力学响应动态演变规律及其对路基稳定性的影响.研究结果表明:铺设土工格栅后路基面差异沉降减小47.1%,墙体最大外倾减小65.4%,路基稳定安全系数提高12.8%;随着剪切强度折减系数增加,填土-土工格栅界面单元滑移失效,但未决定路基稳定性,上层位衡重台外边缘处土工格栅的拉断失效将导致轴向拉力骤降,诱发拓宽路基失稳破坏.
Rigid retaining walls are widely used in highway widening embankments in mountainous regions. To interpret the dynamic development law and mechanics of geogrid reinforced widening embankment with the rigid retaining wall in mountainous region,combined with the particularity of the rigid retaining wall,the finite element software Phase2 and strength reduction method were employed to analyse the stability of geogrid reinforced highway widening embankment in such regions. The interactions between soil and structure were introduced in the established numerical model. The dynamic development law of the mechanical response of the filling,geogrid and filling-geogrid interface,and their influences upon the embankment stability were also discussed. The findings regarding the reinforcement effect obtained from the numerical simulation were verified macroscopically using the geotechnical centrifuge model test results. The results showed that the embankment surface differential settlement was reduced by 47.1%,the maximum wall extraversion was reduced by 65.4%,and the embankment stability factor was increased by 12.8% with the geogrid reinforcement. With the increase in the shear reduction factor,the joint elements between the filling and the geogrid failed （slipped）,but this slip was not responsible for the failure of the subgrade. Thus,the axial tension decreased suddenly owing to the failure of the geogrid in the upper layer,which was located outside the edge of the balancing platform. The tensile failure of the geogrid induced the instability and failure of widening embankment.
作者
蒋鑫
陈滔
吴玉
朱奇炯
耿建宇
邱延峻
JIANG Xin;CHEN Tao;WU Yu;ZHU Qijiong;GENG Jianyu;QIU Yanjun(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Highway Engineering Key Labor-atory of Sichuan Province,Southwest Jiaotong University,Chengdu 610031,China;MOE Key Laboratory of High-Speed Railway Engineering,Southwest Jiaotong University,Chengdu 610031,China;Hangzhou Railway Section,Shanghai Rail-way Bureau,Hangzhou 310009,China;Bridge and Tunnel Engineering Branch,Sichuan Jiaotou Construction Engineering Co.Ltd.,Chengdu 610041,China)
出处
《西南交通大学学报》
EI
CSCD
北大核心
2018年第5期1000-1008,共9页
Journal of Southwest Jiaotong University
基金
国家自然科学基金资助项目(51378440)
国家973计划资助项目(2013CB036204)
中央高校基本科研业务费专项资金资助项目(SWJTU12CX067)
关键词
山区公路
路基拓宽改建
土工格栅
稳定性
有限元
剪切强度折减法
mountain region highway
embankment widening
geogrid
stability
FEM （Finite element method）
shear strength reduction method
