加筋土拉拔界面作用的离散元细观模拟

发布时间：2018-07-23 15:10

【摘要】：为研究加筋土界面作用的力学响应,对离散元程序(PFC3D)进行二次开发,建立了土工格栅拉拔试验仿真模型。与室内模型试验结果进行对比,探讨了拉拔界面细观参数的演变及荷载传递机理,揭示了细观参数的演化规律及其与宏观力学性质之间的关系。研究结果表明:筋土界面区域成为主要的位移集中区,上界面影响厚度略大于下界面影响厚度;在筋土界面区域形成了高度的X向应力集中,沿格栅长度方向出现若干个Z向应力集中区,表明格栅横肋挤压土体,其所提供的被动承载力较为显著;在筋土界面区域,局部孔隙率随拉拔位移增大而增大,接触数减少,滑动比随拉拔位移的增加发生了激烈的跌宕起伏,界面局部位置发生剪胀,宏观上对应拉拔阻力增大,而后孔隙率慢慢减小,拉拔阻力回落。
[Abstract]:In order to study the mechanical response of the interface of reinforced soil, the discrete element program (PFC3D) was redeveloped, and the simulation model of geogrid drawing test was established. Compared with the results of indoor model tests, the evolution of meso-parameters and the mechanism of load transfer at drawing interface are discussed, and the relationship between the evolution of meso-parameters and the macroscopic mechanical properties is revealed. The results show that the interfacial area of reinforced soil is the main concentration area of displacement, the influence thickness of the upper interface is slightly larger than that of the lower interface, and a high degree of X-ray stress concentration is formed in the area of the interface between the reinforcement and soil. Along the direction of grid length, there are several Z stress concentration zones, which indicate that the passive bearing capacity of the cross rib of the grid squeezing soil is significant, and the local porosity increases with the increase of drawing displacement and decreases with the increase of drawing displacement in the interface area of reinforced soil. With the increase of drawing displacement, the sliding ratio fluctuates intensely, the local position of the interface increases, the relative drawing resistance increases, then the porosity decreases slowly, and the drawing resistance decreases.
【作者单位】：广西科技大学土木建筑工程学院;同济大学地下建筑与工程系;广西大学工程防灾与结构安全教育部重点实验室;
【基金】：国家自然科学基金资助项目(51009030) 广西自然科学基金资助项目(2011GXNSFB018003) 广西防灾减灾与工程安全实验室开放课题资助项目(2012ZDK07) 广西科技大学博士基金资助项目(院科博1011)
【分类号】：TU47;TU53

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