墩顶撞击作用下高铁桥墩动力行为研究  

Research on dynamic behavior of high-speed railway bridge piers under impact at pier top

作　　者：孟栋梁 胡仁康 杨孟刚[1,2] 何旭辉 Meng Dongliang;Hu Renkang;Yang Menggang;He Xuhui(Central South University,Changsha 410075,China;National Engineering Research Center of High-speed Railway Construction,Technology,Changsha 410075,China)

机构地区：[1]中南大学,湖南长沙410075 [2]高速铁路建造技术国家工程研究中心,湖南长沙410075

出　　处：《土木工程学报》2024年第12期54-67,共14页China Civil Engineering Journal

基　　金：国家自然科学基金(51978667,52278232);中国博士后基金(2023M733970);中国中铁股份有限公司科技研究开发计划(2021-专项-04-2)。

摘　　要：以往关于桥墩在侧向撞击下的力学行为研究主要关注车辆或驳船的撞击作用,即撞击位置在桥墩中部或墩底。然而,在实际工程中桥墩也可能在墩顶处遭受撞击,例如地震中发生于抗震挡块处的撞击。文章以高铁桥墩为研究对象,通过试验和数值模拟的方法探究缩尺桥墩在墩顶撞击作用下的动力响应。试验结果表明,一个典型的撞击过程包括3个阶段:碰撞阶段I、碰撞分离阶段和碰撞阶段Ⅱ。在碰撞阶段I,撞击荷载主要由构件中的惯性力来平衡;在碰撞阶段Ⅱ,撞击荷载由惯性力和恢复力共同平衡。因此,在发生同等墩顶位移的条件下,构件所承受的撞击荷载会远大于静力荷载,且该现象对于碰撞阶段I尤为显著。数值模拟结果表明,由于惯性效应导致的振动,构件在撞击作用下与在静力作用下的内力发展显著不同。在拟静力作用下,沿桥墩的弯矩呈三角形分布;而在撞击作用下,桥墩截面弯矩发生显著振荡。Previous research on the dynamic behavior of bridge piers under lateral impacts mainly focused on the impact of vehicles or vessels with impact positions at the middle or bottom of piers.However,in actual engineering,bridge piers may also be subjected to impact at the pier top,such as seismic-induced impacts occurring at shear keys.This study takes the high-speed railway bridge piers as the research object.Experiments and numerical simulations were performed to investigate the dynamic response of the scaled piers under impacts at the pier top.The experimental results show that a typical impact process consists of three phases,i.e.,the impact phase I,the separation phase,and the impact phase I.In the phase I,the impact load is mainly equilibrium by inertial force in the pier,but in the phase I it is jointly equilibrium by inertial force and restoring force of the pier.Consequently,in the case of causing the same pier-top displacement,the impact force acting on the pier is much greater than the static force,and this phenomenon is particularly significant in the impact phase I.The numerical simulation further reveals that due to the inertia effect,the development of internal forces in the pier under impact loads is substantially different from that under the static loads.The bending moment along the piers is distributed in a triangle shape when subjected to static loads.In contrast,for the case of impact loads,obvious oscillations are found in the bending moment along the bridge pier.

关 键 词：震致撞击 高铁桥墩 墩顶撞击试验 数值模拟 动力响应 内力发展 

分 类 号：U238[交通运输工程—道路与铁道工程]