重载公路路基动力响应现场测试与三维空间分布规律  

Field Test and Three-dimensional Spatial Distribution of Dynamic Response of Heavy-duty Highway Subgrades

作　　者：崔新壮[1] 包振昊 郝建文 杜业峰 张圣琦 李向阳 赵延涛[2] CUI Xin-zhuang;BAO Zhen-hao;HAO Jian-wen;DU Ye-feng;ZHANG Sheng-qi;LI Xiang-yang;ZHAO Yan-tao(School of Civil Engineering,Shandong University,Jinan 250061,Shandong,Chian;Jinan Urban Construction Group,Jinan 250100,Shandong,Chian)

机构地区：[1]山东大学土建与水利学院,山东济南250061 [2]济南城建集团有限公司,山东济南250100

出　　处：《中国公路学报》2023年第10期75-83,共9页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52027813,U22A20235,52178429);山东省自然科学基金项目(ZR2020ME242)。

摘　　要：交通荷载的“远—近—远”周期性移动,导致作用于路基土体单元上的主应力方向产生连续的旋转及产生复杂的应力路径,从而加剧路基动力性能的衰变,进一步影响路基服役性能。利用自主研发的三维动态土压力传感器(RDSPS),开展了重载交通荷载下公路路基三维动力响应现场测试,获取了真实状态下路基全应力分量(σ_(x)、σ_(y)、σ_(z)、τ_(xz)、τ_(xy)、τ_(yz))时程曲线,揭示了重载交通作用下路基内部复杂应力路径与应力主轴旋转规律,解译了路基动应力的三维空间分布特征,建立了公路路基竖向动应力计算模型。研究结果表明:在汽车轮轴经过土单元过程中,土单元最大应力主轴先是顺时针旋转90°,然后再逆时针旋转90°;在测试速度范围内,汽车速度与轴重对路基动力响应均存在一定影响,但是对于新建公路而言,汽车轴重对动应力的影响更加明显,竖向动应力与汽车速度或轴重呈线性增长的关系,汽车速度与轴重越大,在路基内所产生的竖向动应力越大;不同类型汽车在路基所引起的竖向动应力沿深度方向的衰减规律基本一致,衰减速度由快变慢。该研究对重载公路路基动力性能评价和结构设计提供了基础。A periodic shift in the traffic load causes the continuous rotation of the principal stress direction of subgrade soil elements.Such rotations of the principal stress axis and complex stress path accelerates the deterioration of the dynamic performance of the subgrade and further affects its service performance.In this study,a three-dimensional dynamic response field test was performed on a highway subgrade under heavy-duty traffic load using a self-developed regular dodecahedron soil pressure sensor(RDSPS),and the time history curve of the total stress component(σ_(x)、σ_(y)、σ_(z)、τ_(xz)、τ_(xy)、τ_(yz))of the subgrade under real conditions was obtained,revealing the complex stress path and rotation law of the principal stress axis in the subgrade under heavy traffic.The three-dimensional spatial distribution features of the dynamic stress of the subgrade were then interpreted,and the vertical dynamic stress of the highway subgrade calculation model was constructed.The results indicate that the maximum stress principal axis of the soil element turns clockwise by 90°before turning counterclockwise by 90°when the vehicle's wheel shaft passes through it.For the speed range considered in this study,although the influence of the axle load on the dynamic stress is more visible on new roads,both the vehicle speed and axle load affect the dynamic response of the subgrade.Moreover,the vertical dynamic stress increases linearly with the vehicle speed and axle load.The greater the vehicle speed and axle load,the greater the vertical dynamic stress in the subgrade.The vertical dynamic stress attenuation law generated by the various vehicle types in the subgrade along the depth direction is also essentially the same,and the attenuation speed varies from rapid to slow.Therefore,this study establishes a fundamental basis for dynamic performance evaluation and the structural design of heavy-duty highway subgrades.

关 键 词：路基工程 三维动力响应 现场测试 公路路基 应力路径 应力主轴旋转 

分 类 号：U416.1[交通运输工程—道路与铁道工程]