土工格栅对桩承式路堤土拱效应影响的数值模拟研究

通过plaxis8.5有限元软件,研究大主应力偏转角度的变化,模拟出有无土工格栅时土拱效应的形成及变化规律,分析了填土高度?桩间距?填土的力学参数和本构模型对土拱效应的影响?研究表明:格栅的作用是减弱土拱效应和其本身张拉膜效应以及与垫层之间的摩擦咬合三种作用的叠加;路堤填土的塑性是产生土拱的又一条件;主应力偏转发生在填土初期,达到一定高度时拱达到稳定,且拱轴线并不是由桩顶直接出发,而是在桩顶形成抛物面形的应力核区,拱上应力偏转大致垂直于此抛物面?

Numerical Simulation for Influence of Geogrid on Soil Arching Effect of Elevated Pile-Supported Embankments

Through the plaxis 8.5,the changes of principal stress angle are studied,the forming process and change rules of the soil arching effect whether there is geogrid loading or not are simulated,and the influencing factors to soil arch,such as the height of fill,the space between piles,the mechanical parameters and constitutive model of fill,are analyzed.The study results show that geogrid is the composition result of three effects,such as the geomembrane effect itself,decreased soil arching effec and the friction occlusion effect between cushionlayer and geomembrane itself;The plasticity of embankment filling is another condition for generating soil arch;The principal stress deflection occurs in its early stage,when reaching to a certain height,the deflection angle is unchanged,and the arch becomes stable.In addition,the arch axis does not set out directly from the pileblock,by contrast,the stress area of paraboloid is shaped on the pileblock,and the stress deflection on the arch is approximately perpendicular to the paraboloid.