Simulation Of Dynamic Behaviors Of Ballasted Railway Beds With Discrete Element Method

Railway ballasted track structure is the main form of the railway line in China. In the railway ballasted track structure, track is one of the most important parts of the track structure system, the role of ballast under train load and the indirect transfer to the subgrade and foundation. So, under the outer vertical load, mutual extrusion ballast particles, relative movement and rearrangement, breaking may also happen, vertical caused by uneven subsidence of railway roadbed, resulting in the longitudinal track irregularity, to ensure the safety of train running on the serious threaten. The train will have static and dynamic force load two types of ballast bed, will be on the ballastless elasticity, the vertical settlement and compaction degree have a serious impact, which is the main factor leading to the ballastless frost boiling, compaction. Therefore, the roadbed of railway ballasted track as the research object, according to the size of train static load, the coefficient of friction between the ballast, train cyclic loading and other parameters on the mechanical behavior, the change-rule of ballast bed is very necessary. The deterioration law of the content of this research is helpful to the study of the track, which has a very important practical significance.In this paper, combined with the numerical simulation method of discrete element, on the static and dynamic analysis of mechanical behavior of the cyclic load carrying two forms of the ballast track bed, the main work is divided into the following three: 1. For the irregular geometry of railway ballasted track ballast, use Minkowski sum theory to1. For the irregular geometry of railway ballasted track ballast, use Minkowski sum theory to describe the polyhedral particle model based on the irregular geometry of railway ballast bed of particles, the contact state between the nonlinear contact constitutive model to describe the particle complex, real working condition in order to establish the ballast box test of discrete element simulation model of railway ballast.2. The ballast box discrete element model applied to different size of train static load and the analysis of the time variation of the mechanical parameters; at the same time, the size and the ballast friction coefficient transform numerical analysis of load, the ballast vertical cumulative settlement, affecting the effective stiffness and density etc.. The ballast box discrete element model is applied to the simulation of 150 k N axle load, axle load, the deformation regularity of modulus were discussed and the vertical density under different friction coefficient is relatively large axle load settlement: train load and train load vertical settlement and effective stiffness and density variation different.3. The ballast box discrete element model applied to train cyclic loading, analysis of vertical cumulative settlement, the effective stiffness and density variation with time; at the same time on different period of the train load and ballast friction coefficient is simulated, obtained the influence of load cycles and the friction coefficient of road bed mechanicalbehavior; comparison of train cyclic loading, static the change of mechanical properties of different load.