高速铁路填方路基粗粒土细观力学性质的离散元模拟

基于离散元方法,建立一个表征填方路基粗粒土细观力学性质的颗粒流模型。同时,利用三维颗粒流程序PFC3D的内置FISH语言,进行二次开发,真实地模拟了粗粒土的颗粒级配曲线。通过大量的颗粒流数值模拟试验,准确地标定了表征粗粒土细观力学性质的相关细观参数。计算结果表明:离散元模拟结果和室内土工试验结果基本一致,粗粒土呈现出较大的体缩和体胀性,同时分别对比了不同围压下,路基粗粒土离散元模拟与室内三轴试验下的应力-应变曲线,其变化规律基本一致。

DEM Simulation on Micro-mechanical Behavior of Coarse-grained Soil of Filling Subgrade for High-speed Railway

Based on discrete element method(DEM),a particle flow code(PFC)model representing micro-mechanics properties of coarse-grained soil of filling subgrade was built.At the same time,FISH language program built in three-dimensional particle flow code PFC3D was used to carry out secondary development and simulate the grading curve of the coarse-grained soil truly.This paper,through a large amount of PFC numerical simulation,calibrated the related micro parameters representing the micro-mechanical properties accurately.The result of calculation shows that the result from the DEM simulation agrees to that from indoor soil test substantially and the coarse-grained soil presents obvious shrinkability and expansibility;in addition,under different confining pressure,the stress-strain curves of the coarse-grained soil from DEM simulation and indoor triaxial test were compared respectively and found to have the consistent change rule basically.