精细微观车流-桥梁耦合系统构建及伸缩缝纵向变形分析  

Construction of Fine Microscopic Vehicle-bridge Coupling System and Analysis of Longitudinal Deformation of the Expansion Joint

作　　者：刘焕举 武隽[2] 刘宁 申彦利[1] 李彦苍[1] 张荣 LIU Huan-ju;WU Jun;LIU Ning;SHEN Yan-li;LI Yan-cang;ZHANG Rong(School of Civil Engineering,Hebei University of Engineering,Handan 056038,Hebei,China;School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China)

机构地区：[1]河北工程大学土木工程学院,河北邯郸056038 [2]长安大学公路学院,陕西西安710064

出　　处：《中国公路学报》2021年第12期115-128,共14页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(51908178);河北省高等学校科学技术研究项目青年拔尖人才项目(BJ2020012)。

摘　　要：大跨桥梁上的车流重力动态分布和作用在变形主梁上的时变纵向力,决定梁端伸缩缝纵向变形,实现伸缩缝纵向变形分析,车-桥耦合系统是核心,实现车流重力分布和纵向力计算加载的车流微观行驶行为仿真及力学化的理论方法是关键。首先,从元胞尺寸和行驶规则2个角度对仿真方法进行精细:把实测车型典型轴距对标当前市场车型,确定各车型车辆前、后悬长并纳入车长考虑,基于多车型的车长公约数综合确定元胞尺寸,使得各车型的车长在仿真交通流中得到差异且全面的元胞表达,奠定精细仿真元胞基础;在车间距基础上,把车速差纳入考虑,丰富车辆微观行驶决策因素,并设定多级变速和变道优先权,从宏观规则和处置细节上对车流行驶微观行为进行精细化。其次考虑到车速是车辆行驶行为的直观表现,采用动量定理实现车辆变速行为到纵向力(力矩)的转换;把纵向力(力矩)均分加载在车辆占据的各元胞中心,实现车辆出、入桥力学过程的适度精细模拟;匹配车辆行驶行为,调整车流判断流程和加载识别部分,完善微观车流-桥梁分析系统。最后,以一座斜拉桥为工程背景,对不同密度组成的车流作用下伸缩缝的纵向变形进行分析。结果表明:(1)与单向车流相比,计算密度下双向车流的总体纵向力在均值和极值上的加强度的极值分别为1.6和1.5,即双向车流有相互作用,总体表现为抵消;(2)车流重力因素产生的主梁纵向变形较为稳定,伸缩缝纵向响应时程曲线围绕重力产生的伸缩缝纵向变形均值上下波动,波动幅度总体趋势受密度控制,在正、负(方向)上的极值和均值随车流密度增大大体均呈增大趋势,波动局部受上下行密度差控制,当双向车流密度之和一定时,双向车流的密度差越大,极值和均值就越大;(3)伸缩缝纵向位移服从正态分布,伸缩缝累积行程随车流总密度、上�The dynamic distribution of vehicle gravity and the time-varying longitudinal force acting on the deformed main beam of a long-span bridge determine the longitudinal deformation of the expansion joint at the end of the beam. The vehicle bridge coupling system is the core of the longitudinal deformation analysis, and the key to performing this analysis is the simulation theory method of microscopic driving behavior of vehicle flow, which can realize the calculation and loading of gravity distribution and longitudinal force of vehicle flow. First, the simulation method is refined from two aspects of cell size and driving rules: the typical wheelbase of the measured vehicle is benchmarked with the current market vehicle, the front and rear overhanging lengths of each vehicle are determined and taken into consideration by the vehicle length, and the cell size is determined based on the common divisor of the vehicle length of multiple vehicles, so that the vehicle length of each vehicle can be expressed differently and comprehensively in the simulation traffic flow, which lays the cellular foundation of fine simulation;on the basis of vehicle spacing, the vehicle speed difference is taken into account, the micro driving decision factors are enriched, and the multi-level speed change and lane change priority are set, which realizes the refinement of micro driving behavior from macro rules and disposal details. Second, considering that vehicle speed is the visual representation of vehicle driving behavior, the momentum theorem is used to realize the transformation from vehicle’s speed-changing behavior to longitudinal force(torque), By loading the longitudinal force(moment) evenly in the center of each cell occupied by the vehicle, the moderate fine simulation of the mechanical process of the vehicle entering and leaving the bridge is realized. By matching the driving behavior of vehicles, and adjusting the flow judgment process and load identification part, the microscopic traffic flow bridge analysis system is impro

关 键 词：桥梁工程 车-桥耦合系统 数值模拟 随机车流 伸缩缝 

分 类 号：U441.2[建筑科学—桥梁与隧道工程]