客运专线轨道-路基-地基系统临界速度分析

摘要

In view of actual situation of passenger dedicated line in China, a vibration model of the coupling system of track-subgrade-groundwork under the action of moving load was established, and the critical speed of the track-subgrade-groundwork system was analyzed under the conditions of ballasted track and ballastless track respectively on the embankment. Further on, the influences of deformation modulus and thickness of subgrade bed on the critical speed were discussed. The results show that there is a critical velocity in the track-subgrade-groundwork system under the action of a single moving load, and this critical velocity can be called the critical speed of railway line. Moreover, this critical speed of railway line is mainly dominated by the factors:the flexural rigidity of the track, the vibration mass of the track-subgrade, and the elastic modulus of ground soil. To increase the critical speed of railway line, there are some useful measures as follows: increasing the bending stiffness of track, improving and strengthening the soft ground, and selecting the light subgrade filling material to reduce the vibration mass of subgrade.%针对我国客运专线线路的实际情况，建立移动荷载作用下轨道路基地基耦合系统振动模型，分析路堤上有砟与无砟轨道情况下轨道路基地基系统临界速度，并讨论基床变形模量和基床厚度对系统临界速度的影响。分析结果表明：单个移动荷载作用下轨道路基地基系统中存在一临界速度，可称为线路临界速度；线路临界速度主要由轨道抗弯刚度、轨道路基的参振质量和地基土层的弹性模量决定；提高线路临界速度的措施有：增加轨道抗弯刚度、对软土地基进行改良加固、选用轻质路基填筑材料以减小路基的参振质量。