Abstract
In this paper, a discrete and continuous body coupling algorithm is used to study the dynamic contact characteristics between ballasts and between ballasts and track structures. Firstly, the three-dimensional fine modeling of ballast particles is realized based on the three-dimensional laser scanning method, and then through the discrete and continuum coupling algorithm from the micro-macro point of view, a multiscale and unified particle-track structure coupling model is established. Based on the coupling model, the macro- and microdynamic characteristics of the ballast bed and the mechanical characteristics of the track structure under the dynamic load of high-speed trains with different driving speeds are studied. It is shown that the cumulative settlement of the ballast bed is directly proportional to the contact force and rotation speed of the ballast, and the faster the driving speed is, the greater the cumulative deposition speed and cumulative settlement of the ballast are. The contact force between the ballast and sleeper mainly comes from the bottom of the sleeper, and its contact force and contact strength increase with the increase of driving speed.
Highlights
Ballasted track is an important part of the track structure of high-speed railway, which has the advantages of good elasticity, easy maintenance, and fine noise absorption
As a key part of the ballast track structure, the ballast bed is mainly composed of crushed stone ballast, which directly suffers the train load transmitted by sleepers
In viewing the current research results, they mainly suffer from the following problems: (1) the numerical model is mostly based on two-dimensional dynamics and some three-dimensional calculation models are all scaled models; (2) the major objective is on the interaction between the ballast bed and the lower subgrade foundation, while only few of them focus on the interaction between the ballast bed and the upper track; and (3) the calculation process does not consider the adjacent sleepers, such that it cannot fully simulate the high-speed moving train load
Summary
Ballasted track is an important part of the track structure of high-speed railway, which has the advantages of good elasticity, easy maintenance, and fine noise absorption. In viewing the current research results, they mainly suffer from the following problems: (1) the numerical model is mostly based on two-dimensional dynamics and some three-dimensional calculation models are all scaled models; (2) the major objective is on the interaction between the ballast bed and the lower subgrade foundation, while only few of them focus on the interaction between the ballast bed and the upper track; and (3) the calculation process does not consider the adjacent sleepers, such that it cannot fully simulate the high-speed moving train load. E mechanical characteristics and micromechanism of the ballast bed and continuous track structure under the dynamic load of high-speed train are studied, and the rationality of the model is verified by comparing with the existing research results. The distributed control loading mode is adopted to load the cyclic load with a certain phase difference on the three sleepers to simulate the moving load of the high-speed train. e mechanical characteristics and micromechanism of the ballast bed and continuous track structure under the dynamic load of high-speed train are studied, and the rationality of the model is verified by comparing with the existing research results. e relevant conclusions can provide scientific basis for the design and regulation of the ballasted track, and the model can provide a reference for the further design of the test model and the design of the corresponding loading control system
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