列车荷载作用下新型预应力路基振动特性研究  

Study on vibration characteristics of a new prestressed subgrade under train loads

作　　者：董俊利 冷伍明[1,2] 徐方[1,2] 张期树[1,3] 李忠 阮波 姚康[1] DONG Junli;LENG Wuming;XU Fang;ZHANG Qishu;LI Zhong;RUAN Bo;YAO Kang(School of Civil Engineering,Central South University,Changsha,Hunan 410075,China;MOE Key Laboratory of Engineering Structures of Heavy Haul Railway,Central South University,Changsha,Hunan 410075,China;School of Civil Engineering,Center South University of Forestry and Technology,Changsha,Hunan 410004,China;Hunan Tieyuan Civil Engineering Testing Co.,Ltd.,Changsha,Hunan 410004,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学重载铁路工程结构教育部重点实验室,湖南长沙410075 [3]中南林业科技大学土木工程学院,湖南长沙410004 [4]湖南铁院土木工程检测有限公司,湖南长沙410004

出　　处：《岩石力学与工程学报》2023年第11期2847-2860,共14页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51978672);中南大学研究生自主探索创新项目(2021zzts0230);湖南铁院土木工程检测有限公司检测研究基金项目(HNTY2021K09)。

摘　　要：掌握预应力路基在列车荷载作用下的工作性状和加固机制可为其工程设计提供技术参考。通过开展1∶5的缩尺模型试验,探究列车轴重和预应力对路基加速度响应的影响,并建立预应力路基三维动力有限元模型,重点分析预应力路基加速度场的分布特性及预应力加固机制。结果表明:(1)在列车动荷载循环加卸载作用下,路基竖向加速度响应的波峰和波谷均在小范围内波动变化,可采用波峰和波谷均值来反映路基的长期振动程度;(2)路肩位置处竖向加速度峰值随列车轴重和预应力的增加分别呈线性递增关系和指数型衰减关系,建立了描述加速度峰值、列车轴重和预应力三者关系的经验模型;(3)路基竖向加速度峰值与预应力水平存在高度相关性,且加速度响应沿路基横向与深度方向传播时衰减明显,侧压力板周边区域受预应力的影响程度显著高于路基内部区域;(4)水平预应力可减小路基的竖向振动,通过调整预应力大小和增大路基坡率等措施,可实现对路基核心区域的有效加固。研究结果对于进一步了解预应力路基的加固机制具有一定参考意义。Studying the operation performance and reinforcement mechanism of prestressed subgrades under train loads can provide technical references for engineering design.In this study,a 1∶5 scale model test was performed to explore the effect of the train axle load and the prestress on the acceleration response of the subgrade,and a threedimensional dynamic finite element model of the prestressed subgrade was then established to analyze the distribution characteristics of the acceleration field and the prestress reinforcement mechanism.The results show that:(1) Under the action of the cyclic train loading,the peak and trough of the vertical acceleration of the subgrade fluctuate in a small range,and their mean value can be used to reflect the long-term vibration degree of the subgrade.(2) At the shoulder of the subgrade,the peak vertical acceleration linearly increases with increasing the train axle load and exponentially decreases with increasing the prestress,and an empirical model is then established to describe the relationship among the peak acceleration,the train axle load and the prestress.(3) The peak vertical acceleration exhibites a highly correlation with the prestress level,and the acceleration significantly attenuates while propagating along the transverse and depth directions of the subgrade.Therefore,the zones around the lateral pressure plate is significantly affected by the prestress comparing with the inner zones of the subgrade.(4) The horizontal prestress could alleviate the vertical vibration of the subgrade,and the core zones of the subgrade can be effectively enhanced by adjusting the prestress level and increasing the subgrade slope rate.The research findings can provide references for further understanding the reinforcement mechanism of the prestressed subgrade.

关 键 词：路基工程 预应力路基 模型试验 加速度响应 数值仿真 加固机制 

分 类 号：U213[交通运输工程—道路与铁道工程]