换枕车扒砟过程中扒齿下插阻力特性研究

Study on characteristics of insertion resistance of rake teeth during ballast removal

基于莫尔库伦准则,研究换枕车扒齿在匀速垂直下插过程中道床的极限平衡状态以及扒齿下插阻力的变化规律。采用离散元法建立扒齿与道砟间的作用模型,从力链尺度上分析道床的失稳破坏与扒齿阻力的变化机理。研究结果表明:道床在极限状态下所发生的剪切滑移是引起扒齿底部道砟颗粒间力链迅速弯曲断裂的主要因素,力链的断裂进一步扩大道床的失稳破坏范围;扒齿下插阻力随扒齿底部力链的生成与断裂而出现波动且整体随下插深度的增加而变大。

In order to study the limit equilibrium state of the ballast bed and the change law of the rake teeth resistance during the uniform insertion of the teeth into the ballast bed,the Mohr-Coulomb criterion in the granule mechanics was selected.This paper uses discrete element method to establish the interaction model between the rake teeth and the ballast,and analyzes the mechanism of the instability and resistance of the track bed from the force chain scale.The results show that the shear slip occurred in the limit state of the track bed is the main factor causing the rapid bending and fracture of the force chain at the bottom of the teeth and the fracture of the force chain further expands the instability failure range of the ballast bed.The resistance of the teeth insertion fluctuates with the formation and fracture of the force chain at the bottom of the teeth and the resistance increases with the increase of the depth of the insertion.