格栅节点加强对风积沙筋土界面力学性能的影响

Influence of node strengthening on mechanical properties of aeolian sand-geogrid interface

在普通双向土工格栅上附加节点,可形成具有立体加筋效果的加强节点土工格栅。在普通双向土工格栅加筋风积沙拉拔试验和离散元数值模型的基础上,构建加强节点土工格栅加筋风积沙的三维离散元拉拔模型,研究加强节点排布方式、厚度、数量、相邻节点间距对筋土界面力学性能的影响。研究结果表明:在节点上侧加强、节点下侧加强和节点上、下两侧同时加强的排布方式中,上下两侧同时加厚对极限拉拔阻力和界面摩擦角的增幅最大;加强节点可优化土工格栅的加筋性能;当节点布置方式不变时,加强节点厚度和节点数量均与极限拉拔阻力增量呈现出良好的线性相关性;与普通土工格栅相比,加强节点土工格栅的剪切带范围更大,且限制土体位移的能力更强;当多个节点同时工作且相邻节点的间距较小时,相邻节点的影响区域互相重叠,使节点提供的极限拉拔阻力增量降低,产生节点群体效应;随着相邻节点的间距增大,节点影响区域的重叠范围减少,群体效应逐渐减弱。

The geogrid with a three-dimensional reinforcement effect can be formed by attaching the nodes to the biaxial geogrid.Based on the pull-out test of biaxial geogrid-reinforced aeolian sand,a three-dimensional discrete element pull-out model was built.The effects of arrangement,thickness,number and distance between adjacent nodes of strengthened nodes on macro and microscopic mechanical properties of reinforced soil interface were studied.The results show that in the three arrangements of strengthening on the upper side of the node,strengthening on the lower side of the node,and simultaneous strengthening on both the upper and lower sides of the node,the simultaneous thickening on both the upper and lower sides showed the greatest increase in the ultimate pullout resistance and the interfacial friction angle.The reinforced node optimizes the reinforcement performance of the geogrid.When the node arrangement is unchanged,the thickness and number of reinforced node have a good positive linear correlation with the ultimate pullout resistance increment.Compared with the ordinary geogrid,the shear band range of the reinforced node geogrid is larger,and the ability to limit the displacement of soil is stronger.If multiple nodes work at the same time and the spacing of adjacent nodes is small,the influence areas of adjacent nodes overlap each other,which reduces the ultimate pullout resistance increment provided by nodes,resulting in node group effect.As the spacing of adjacent nodes increases,the overlapping range of adjacent nodes decreases,and the group effect gradually weakens.