重载列车作用下隧道基底荷载特征及动力学响应分析

Base Load Characteristics and Dynamic Response Analysis of Tunnel Under Heavy Haul Train

通过对朔黄铁路三家村隧道基底在重载列车作用下的现场测试,统计分析了不同围岩区段基底填充层的动应力幅值,借助于静态换算土柱法,获得了基底的冲击系数。以此为基础,建立了列车-隧道-轨道结构耦合分析模型,分析了列车振动荷载作用下隧道基底结构的动态响应及冲击系数。结果表明:不同围岩级别下钢轨下方动静比平均值分布在1.8～2.08之间,道心处动静比平均值分布在1.0～1.1之间,钢轨下方的动静比约为道心处的2倍,理论计算与实测冲击系数误差最大为7.4%。另外,采用换算荷载推演大轴重列车的荷载特征是可行的,以此确定的基底填充表面的动应力约为120 kPa。

Through field test on the San-jiacun tunnel base on Shuohuang railway under heavy haul train,the statistical analysis of the dynamic stress amplitude of fill layer to different section of surrounding rock is conducted.By means of static translation of the soil column,the impact coefficient of the substrate is acquired.On this basis,by establishing train-tunnel-track structure coupling analysis model,the dynamic response and impact factor of tunnel base structure are analyzed.The results show that： the average dynamic to static ratio of the different levels of surrounding rock under the bottom of the rail varies between 1.8 and 2.08;the average dynamic to static ratio at the line center is in the range of 1.0 to 1.1,and the average dynamic to static ratio at the bottom of the rail is about 2 times at the line center.The theoretical calculation and the measured impact coefficient error is of 7.4%.In addition,it is feasible to deduce the load characteristic of the heavy load train by using translation load and the surface dynamic stress of base fill layer is approximately 120 kPa with above method.