组合Clump颗粒加筋砂土三轴剪切试验离散元模拟分析

Simulation analysis of triaxial shear test of multi-sphericity Clump particles discrete element reinforced sand

针对常规离散元数值模拟中采用的球形颗粒难以再现颗粒间嵌锁作用的问题,基于不同形状的Clump颗粒,利用离散元软件PFC^(3D)开展了多组三轴剪切数值模拟试验.通过改变球形度和加筋层数研究了颗粒形状和加筋层数对砂土剪切特性的影响,并初步探讨了筋土界面作用机理.结果表明:随着颗粒球形度的增加,试样峰值抗剪强度与残余强度逐渐减小;试样中部孔隙率增加,上部孔隙率减小,其剪胀现象更加明显;抗剪强度指标c、φ值与球形度n存在二次函数关系;黏聚力随着球形度的增加减小速度变缓;而内摩擦角的减小速度随着球形度的增加变快;三轴应力强度峰值随加筋层数增加而增加,但3层加筋的峰值较2层加筋的峰值较为接近,增幅为5.9%;采用组合Clump颗粒可以有效模拟不同形状砂土颗粒,对以后的数值模拟具有一定的借鉴意义.

In view of the problem that the spherical particles used in conventional discrete element numerical simulations are difficult to reproduce the inter-particle interlocking effect,multiple sets of three-axis simulation experiments were carried out using the discrete element software PFC^(3D),based on the Clump particles of different shapes.The influence of particle shape and number of reinforcement layers on the shear behavior of sand was studied by changing the sphericity and number of reinforcement layers,and its interface interaction mechanism is preliminarily discussed.The results show that with the increase of particle sphericity,the peak shear strength and residual strength of the sample gradually decrease,the porosity of the middle part increases,and the porosity of the upper part decreases,and the dilatancy phenomenon becomes more obvious;There is a quadratic function relationship between the shear strength index c,φ and the sphericity n.The cohesion decreases slowly with the increase of the sphericity,while the internal friction angle decreases quickly with the increase of the sphericity.The peak value of the triaxial stress intensity increases with the increase of the number of layers,but the peak value of the three-layer reinforcement is closer to that of the two-layer reinforcement,with an increase of 5.9%.Multi-sphericity Clump particles can effectively simulate sand particles of different shapes,which has certain reference significance for future numerical simulation.