Discrete element modelling of railway ballast performance considering particle shape and rolling resistance
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Discrete element modelling of railway ballast performance considering particle shape and rolling resistance Yunlong Guo1 • Chunfa Zhao2 • Valeri Markine1 • Can Shi2 • Guoqing Jing3 Wanming Zhai2
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Received: 11 May 2020 / Revised: 14 July 2020 / Accepted: 20 July 2020 The Author(s) 2020
Abstract To simulate ballast performance accurately and efficiently, the input in discrete element models should be carefully selected, including the contact model and applied particle shape. To study the effects of the contact model and applied particle shape on the ballast performance (shear strength and deformation), the direct shear test (DST) model and the large-scale process simulation test (LPST) model were developed on the basis of two types of contact models, namely the rolling resistance linear (RRL) model and the linear contact (LC) model. Particle shapes are differentiated by clumps. A clump is a sphere assembly for one ballast particle. The results show that compared with the typical LC model, the RRL method is more efficient and realistic to predict shear strength results of ballast
& Can Shi [email protected] Yunlong Guo [email protected] Chunfa Zhao [email protected] Valeri Markine [email protected] Guoqing Jing [email protected] Wanming Zhai [email protected] 1
Faculty of Civil Engineering and Geosciences, Delft University of Technology, 2628CN Delft, The Netherlands
2
Train and Track Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
3
School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China
assemblies in DSTs. In addition, the RRL contact model can also provide accurate vertical and lateral ballast deformation under the cyclic loading in LPSTs. Keywords Discrete element method Ballast performance Boundary condition Rolling resistance Direct shear test Lateral displacement
1 Introduction Railways play a significant role in the transportation system worldwide and work in many sectors (urban rail, highspeed railway, heavy haul, intercity and metro) [1, 2]. Ballasted tracks, as the most widely used track type, consist of rails, sleepers and the ballast layer [3, 4]. It possesses the advantages such as low construction cost, simple design and construction, and easy maintenance [5]. The ballast layer, a crucial component of ballasted track, provides resistances to sleepers, transmits and distributes the loads or impacts from sleepers to the subgrade, as well as allows rapid drainage [6]. Generally, it is composed of blasted (quarried) rock aggregate, which is required to meet certain characteristics such as narrow-graded (20–60 mm) and irregular particle shape, specific surface roughness, density, hardness, resistance to attrition and weathering [7]. Even though various railway ballast standards in terms of particle size distribution or particle shape have already been formulated [7–9], their influences on ballast performance (resilience, shearing strength, and settlement) have not been sufficie
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