Maintenance Mechanism of Ballast Tamping and Stone-Blowing Using Discrete Element Method
In order to study the maintenance mechanism of ballast tamping and stone-blowing from a micro view,a ballast box numerical model using the discrete element method was established,and the whole processes of ballast tamping and stone-blowing were visually simulated by coupling the tamping hammer model of multi-body dynamics and the blowing tube model of computational fluid dynamics.Based on the discrete element coupled numerical simulation,the effects of two ballast maintenance methods on ballast disturbance and sleeper settlement after operation were compared.The results show that the ballast disturbance and the average contact force of the ballast of the stone-blowing are less than those of the tamping,and the disturbance is mainly concentrated in the insertion stage.Moreover,the peak velocity and contact stress of ballast particles during the stone-blowing are only 37.5%and 38.9%of those during the tamping.After tamping,the compactness at the bottom of the sleeper is increased by about 13.6%,and the compactness of the upper and lower areas between sleepers is reduced by about 21%and increased by about 4.8%,respectively.After stone-blowing,the compactness at the bottom of the sleeper is increased by about 6.5%,and the compactness of the upper and lower areas between sleepers is almost unchanged.Due to the stone-blowing beneath the sleeper,the stone-blowing greatly improves the contact state and stress diffusion at the bottom of the sleeper.The contact number between the sleeper and the ballast particles increases by about 243%,which makes the load transfer more uniform.After 1 000 cycles of loading,the sleeper settlement after stone-blowing is reduced by about 18.1%and 44.4%respectively compared with tamping and unmaintained conditions.
ballastdiscrete element methodtampingstone-blowingballast maintenance
万方数据
维普
