级配对粗粒土力学特性影响的颗粒流模拟研究

运用三维颗粒流软件PFC3D的内置FISH语言,进行二次开发,模拟粗粒土真实级配,建立一个研究高铁填方路基粗粒土力学特性的颗粒流模型,标定了表征粗粒土细观力学性质的模型参数,并验证了模型的有效性。考虑粗粒土曲率系数和不均匀系数对颗粒级配的影响,模拟并研究了五种不同级配下粗粒土在三种不同围压下的力学特性。结果表明:当粗粒土有效粒径与中值粒径及限制粒径的差距过大时,粗粒土中颗粒填充及致密性将变差,变形增大,强度降低;级配良好且不均匀系数较大,其力链分布越均匀,颗粒的挤压效果越显著,力的传递和分配也越均匀。

Research on Particle Flow Simulation of Influence of Grading on Mechanical Property of Coarse-grained Soil

The Fish language in built in three-dimensional particle flow software PFC3D is adopted to make secondary development, simulate the real grading of coarse-grain size soil and establish a particle flow model for researching the mechanical property of coarse-grained soil in high-speed railway fill subgrade. The model parameters representing mesomechanics property of coarse-grain size soil are marked and the validity of model is verified. Considering the influence of the curvature coefficient and the nonuniform coefficient on the grain size grading, the mechanical property of five kinds of coarse-grained soil with different grading curves under three different confining pressures are simulated and studied. The results show that if there is big difference among effective grain size, median diameter and constrained size, the particle filled coarse-grained soil and its compactness will have the problem of performance deterioration and the deformation and stress capacity will decrease. With good grading condition, the larger the nonuniform coefficient is, the more remarkable the compactness and the more even the force chain distribution are. What’s more, the extrusion effect of particle becomes more obvious and the transfer and distribution of force are more uniform.