轨枕空吊动态演变规律

Dynamical Evolution Process of Voided Sleeper

在车辆-轨道耦合系统动力学模型和道床沉降模型的基础上,提出了一种基于迭代计算的预测方法,对轨枕局部空吊后的动态演变过程进行了合理的预测.结果表明:当轨枕单侧轨底处出现局部空吊时,空吊区域的承载力明显降低,而与之相邻区域承受的车辆载荷增加,导致相邻区域轨枕空吊间隙发展较快,从而形成空吊区域由轨枕两端轨底处向轨枕中心扩展的动态演变过程;随着轨枕空吊区域的不断扩大,整根轨枕的承载力大幅降低,大部分列车载荷主要由相邻未出现空吊的轨枕承担,因而轨枕的空吊发展程度逐渐趋于平缓,最终大部分区域存在1.5 mm左右的空吊间隙.

In order to employ the dynamical evolution process of voided sleeper, an iterative computation method based on the vehicle-track coupled system dynamics model and subgrade settlement model is proposed in this paper. Simulation results indicate that when one end of the sleeper has an initial gap between the sleeper and subgrade, the sleeper-subgrade contact force at this area decreases obviously. On the other hand, the sleeper-subgrade contact force at the adjacent areas increases. Therefore, the sleeper voided area expands from one end to central part. Moreover, with the increased voided area the supporting capability of the sleeper deteriorates largely and most of the train loads are shared by the other sleepers. Due to this reason, the voided degree of the sleeper trends to be stable, and most areas have a gap about 1.5 mm.