土工格栅与砂土接触界面细观特性离散元研究

Study on mesoscopical properties of interface between geogrid and sand by DEM

为研究复杂的筋土相互作用机制,采用内置'clump'方法开发了可模拟砂土性状的椭球形颗粒,建立了三维颗粒流数值模型,在不同法向应力下进行了一系列拉拔数值试验.从细观角度验证了接触力及筋土界面颗粒位移特征,并通过量化分析揭示了摩擦阻力及承载阻力发展规律.结果表明:拉拔过程中界面区域内出现剪胀;当拉拔位移较小且法向应力较高时,两阻力分量增速较一致,拉拔位移较大时,拉拔力增量主要来源于承载阻力的增长.

To investigate the complicated mechanism of interaction between geogrid and soils,elliptical group particles were developed by adopting the inherent ＂clump＂ logic to simulate the properties of sand particles factually.Based on the particle flow code in three-dimension（PFC3D）,a numerical model was established to conduct a series of pull-out tests under different normal stresses.The contact forces and displacement characteristics of particles were verified mesoscopically.Friction and bearing resistances were quantitatively analyzed.The results show that the dilation occurs in the area of interface;two kinds of resistances increase simultaneously under smaller pull-out displacement when the vertical stress is larger,and the increment of total pull-out resistance is mainly attributed to the increasing of bearing resistance when the displacement becomes larger.