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Stress on ballast-Bed and Deterioration of Geometry in a railway Track

Journal of Civil Engineering and Architecture 2010年第6期4卷 27-42页

作者： Konstantinos Giannakos Department of Civil Engineering University of Thessaly Pedion Areos Volos 38334 Greece

In Greece extended cracking of twin-block concrete sleepers （ties） and fouling of the ballast-bed were observed with implied problems of gauge widening and deterioration of track＇s geometry. This led to a ten-year investigation program, during which a new method was developed for the estimation of actions on track panel as well as of the pressures / stresses that develop under the seating surface of the sleeper on the ballast-bed. Results from the tests performed on the ballast used in the Greek network are also presented, conducted in laboratories in France, Austria, and Greece. The influence of the actions -static and mainly dynamic- on the track response and the stress and strain of the ballast-bed are also discussed as derived from the tests and theoretical analysis.

关键词： railway ballast ballast hardness actions on track mean stress on ballast bed cracked concrete ties.

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Macro-microscopic dynamic characteristics of the ballast bed induced by the variation of moisture content

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Particuology 2024年第7期90卷 118-127页

作者： Shuchen Wang Longlong Fu Yongjia Qiu Haonan Xi Shunhua Zhou Key Laboratory of Road and Traffic Engineering of the Ministry of Education Tongji UniversityShanghai 201804China Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety Tongji UniversityShanghai 201804China

Due to the excellent drainage performance of the ballast,existing studies mainly focus on the dynamic response of ballast under field capacity or *** has rarely been paid to dynamic changes in moisture content and potential *** this article,we firstly conduct a model test to determine the variation of ballast moisture content under artificial *** that,a full-scale model test with cyclic loading is carried out to study the effect of moisture content variation on the macro-microscopic response of the ballast bed,where several wireless particle sensors are installed to obtain ballast motion characteristics at strategic *** results show that the moisture content increases gradually and stabilizes at a flat peak under rainfall,despite the excellent drainage performance of ballast *** halting rainfall,the moisture content drops back to field capacity,which indicates dynamic flowing surface water on ballast particles under *** flowing surface water brings changes to the original dynamic equilibrium of ballast bed:macroscopically,the deformation rate of stabilized ballast bed increases significantly,reaching a local peak under field capacity;microscopically,the x-and z-angular accelerations of the ballast show positive correlation with rainfall *** multiscale responses indicate that field capacity is a critical moisture content.

关键词： railway ballast Flowing surface water Wireless particle sensor Multidimensional motion Full-scale model test

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Study on the particle breakage of ballast based on a GPU accelerated discrete element method

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Geoscience Frontiers 2020年第2期11卷 461-471页

作者： Guang-Yu Liu Wen-Jie Xu Qi-Cheng Sun Nicolin Govender State Key Laboratory of Hydroscience and Hydraulic Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing 100084China Department of Chemical Engineering University of SurreyUnited Kingdom

Breakage of particles will have greatly influence on mechanical behavior of granular material(GM)under external loads,such as ballast,rockfill and *** discrete element method(DEM)is one of the most popular methods for simulating GM as each particle is represented on its *** study breakage mechanism of particle breakage,a cohesive contact mode is developed based on the GPU accelerated DEM code-Blaze-DEM.A database of the 3D geometry model of rock blocks is established based on the 3D scanning *** an agglomerate describing the rock block with a series of non-overlapping spherical particles is used to build the DEM numerical model of a railway ballast sample,which is used to the DEM oedometric test to study the particles’breakage characteristics of the sample under external ***,to obtain the meso-mechanical parameters used in DEM,a black-analysis method is used based on the laboratory tests of the rock *** on the DEM numerical tests,the particle breakage process and mechanisms of the railway ballast are *** results show that the developed code can better used for large scale simulation of the particle breakage analysis of granular material.

关键词： Discrete element method(DEM) Particle breakage Graphical processing unit(GPU) railway ballast Granular material(GM)

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Inconsistent effect of dynamic load waveform on macro-and micro-scale responses of ballast bed characterized in individual cycle:a numerical study

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railway Engineering Science 2023年第4期31卷 370-380页

作者： Longlong Fu Yuexiao Zheng Yongjia Qiu Shunhua Zhou Key Laboratory of Road and Traffic Engineering of the Ministry of Education Tongji UniversityShanghai 201804China Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety Tongji UniversityShanghai 201804China Municipal Public Engineering Design Institute Shanghai Urban Construction Municipal Engineering(Group)Co.LtdShanghai 200065China

Cyclic load is widely adopted in laboratory to simulate the effect of train load on ballast *** effectiveness of such load equivalence is usually testified by having similar results of key concerns of ballast bed,such as deformation or stiffness,while the consistency of particle scale characteristics under two loading patterns is rarely examined,which is insufficient to well-understand and use the load *** this study,a previous laboratory model test of ballast bed under cyclic load is rebuilt using 3D discrete element method(DEM),which is validated by dynamic responses monitored by high-resolution ***,train load having the same magnitude and amplitude as the cyclic load is applied in the numerical model to obtain the statistical characteristics of inter-particle contact force and particle movements in ballast *** results show that particle scale responses under two loading patterns could have quite deviation,even when macro-scale responses of ballast bed under two loading patterns are very *** inconsistency indicates that the application scale of the DEM model should not exceed the validation ***,it is important to examine multiscale responses to validate the effectiveness of load simplification.

关键词： railway ballast Particle movements Contact distribution Waveform sensitivity 3D discrete element method

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Study on Influence of ballast Spring Modulus on Track Structure Based on Finite Element Method

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Frontiers Research of Architecture and Engineering 2021年第2期4卷 30-35页

作者： Tian Yang China railway(Tianjin)rail transit investment and Construction Co. Ltd.Tianjin300000China

The finite element method is used to simulate the orbital structure,and the finite element model of"rail-sleepers-ballast"can be *** model of the elastic modulus of different ballast and sleeper is calculated,and the rail displacement,the sleeper stress and the fastening force are *** results show that the elastic modulus of the ballast can be increased to reduce the displacement of the rail and the supporting force of the fastener,but the stress of the sleeper will be *** the modu-lus of elasticity increases,the rail displacement,small.

关键词： railway ballast Elastic modulus Finite element method

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