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Date of Publication:2022-10-10

Journal:固体力学学报

Affiliation of Author(s):运载工程与力学学部

Volume:37

Issue:5

Page Number:444-455

ISSN No.:0254-7805

Abstract:Ballast is a special kind of geotechnical materials with obvious
   discrete characteristics.The non-uniform settlement of ballast resulting
   from long-term train loadings influences the regularity and stability of
   ballasted track and threatens the safety of passing trains.Geogrid
   reinforcement for railway ballast is an effective and economic method to
   strengthen the ballasted track.The discrete element method (DEM)has
   advantages in simulating discrete media,especially the ballast
   material.In order to study the effect of geogrid reinforcement on the
   ballast,this paper presents a coupled discrete-finite element method to
   investigate the interaction between geogrid and ballast particles.The
   clumps are employed to simulate the irregular shape of ballast
   particles;the beam elements are used to compute the response of geogrid;
   and the transmission of dynamic parameters on the contact interface is
   realized between the discrete and the finite element areas.The effect of
   geogrid reinforcement on the ballasted track under cyclic loadings is
   analyzed. To further study the mechanism of geogrid reinforcement,direct
   shear tests are conducted on the reinforced ballast particles.The
   results indicate that lateral and vertical displacements are both
   obviously decreased by the geogrid reinforcement.Geogrid can provide
   ballast particles with horizontal restraint and help to maintain the
   track geometry.The cohesive force and friction angle of ballast material
   are both enhanced after reinforced with geogrid.Geogrid can strengthen
   the interlock between ballast particles,enhance the strength of ballast
   material and prevent the shear band in the upper box from propagating
   into the nether box.According to the above conclusions,geogrid
   reinforcement is a valid technique to enhance the carrying capacity of
   ballasted track.In the high-speed and heavy-duty railway section,the
   installation of geogrid in ballast could contribute to enhancing the
   stability of ballasted track and reducing the maintenance costs.The
   coupled discrete-finite element model is applicable to simulating the
   behavior of geogridreinforced ballast.

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