Numerical Simulation The Mechanical Characteristics Of Coarse Grained Soil With The Influence Of Particle Size Distribution

China’s economy developed with a high speed in recent years.Recent years,C hina has set off a new upsurge of economic construction.To alleviate traffic pressure,mak ing traffic to meet the needs of the rapid development of economy,China improves the technology of high speed railway."C hinese high-speed railway" has become a foreign calling card of the C hinese.As a coarse grained soil of high speed railway subgrade filler to adapt to the demanding requirements of the high-speed train traveling on the subgrade settlement and stability,mechanical properties and stability of its own research is particularly important and urgent,which is today’s domestic and foreign scholars have a important research topic.There are many factors affecting the mechanical properties and stability of coarse grained soil and the particle size distribution is one of the most influential factors.Particle size distribution affects not only the mechanical properties and deformation performance of coarse grained soil under static loading,but also the accumulated permanent deformation under cyclic loading,and permanent deformation of coarse grained soil is directly related to settling volume which is a key controlling factors to the quality of high speed railway subgrade.It is appropriate and necessary to use discrete element method to study the mechanical properties of coarse grained soil as a kind of non-cohesive discrete material.In this paper,the discrete element software PFC3 D is used to simulate the mechanical properties of coarse grained soil.The main research contents are as follows:(1)referencing Akke S.J.suiker’s three axial compression test on high speed railway subgrade fil er of coarse grained soil,using the particle size distribution in the experiment,the PFC3 D model is established to simulate the coarse-grained soil three axis test.Contrasting the laboratory test and simulation test results,the calibration of microscopic parameters of the model has been made,and verified the validity of the numerical model.(2)the calibrated model parameters,gradation generator was developed by means of the software PFC3 D fish language embedded,generate different gradation of coarse grained soil model and Simulation of triaxial test,to explore the static load lower pairing coarse grained soil under impact force and deformation performance.(3)analyzed the gradation of coarse grained soil subgrade cumulative permanent deformation effect under cyclic loading.