The Impact of Discrete Ballast Particle Modeling Based on Improved Inscribed Circle Method on Two-Dimensional Ballast Angle of Repose and Ballast Bed Settlement
In this study,we improved the method of combinatorial modelling of disk tangents.Based on the two-dimensional contour of real ballast particles,the discrete element inscribed model of ballast particles was estab-lished by the zonal maximum inscribed circle method,the contour refinement model was established by dense small disc filling at the edge of the inscribed model contour,and the filling model was established by the densest hexagon method using the same contour.Then,we carried out the angle of repose test of hollow column lifting of ballast particles to verify the correctness of the model and obtain the main discrete element parameters of the model.On this basis,these three models were used to fill the same ballast bed in numerical simulation experi-ments,and the macroscopic mechanical properties of the ballast bed were analysed by applying a cosine load with a load amplitude of 5～30 kN and a loading frequency of 5 Hz to the sleeper.It is shown that the refinement of the contour model is computationally efficient and highly refined and can better model particle damage.The shape of the particles and the friction coefficient are sensitive to changes in the angle of repose,and the fine model has a good pile-up performance.The degree of refinement in the modelling of the ballast particles has a large effect on the performance of the ballast bed.The mechanical properties of the refinement of the contour model and the filling model are similar in the angle of repose test and the ballast bed test.The former has lower computational costs and promising application prospect in the two-dimensional discrete element ballast bed models.
maximum tangent circlecontour refinementcomputational costangle of reposeballast bed perform-ance
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