摘要
为了给应用落锤式弯沉仪(falling weight deflectometer,简称FWD)准确识别路基性能劣化提供理论基础,建立了考虑路基非饱和特性的弹性层状路面在FWD荷载作用下的振动响应计算模型。通过Laplace-Hankel变换对模型的动力控制方程进行了推导求解,建立了路面和非饱和路基的动力刚度矩阵。并由层间连续性条件合成了公路结构的整体动力刚度矩阵,结合边界条件得出了FWD荷载作用下整个公路结构在变换域内的振动响应解。利用Laplace-Hankel逆变换对振动响应进行了空间-时间域内的数值求解,分析了FWD荷载频率和路基饱和度对振动响应的影响以及路基性能劣化与路表振动信号的关联性。研究结果表明:路表竖向动位移主要受FWD荷载低频成分的影响且随饱和度的增大而增大;相比较路表振动速度和路基表面竖向动应力,路表竖向动位移受路基性能劣化的影响更敏感,且在距荷载中心1.2 m位置处的路表竖向动位移变化率达到最大。研究结果可为路基性能劣化的反馈指标与位置选择提供科学依据。
A vibration response calculation model of elastic layered pavement under the falling weight deflectometer(FWD)load considering the unsaturated characteristics of the subgrade is established to provide the theoretical basis for accurately identifying subgrade performance deterioration by using FWD.The dynamic governing equations of the model are derived and solved by Laplace-Hankel transformation,and the dynamic stiffness matrices of the pavement and unsaturated subgrade are established.The global dynamic stiffness matrix of the highway structure is synthesized from the interlayer continuity condition,and the vibration response solution of the entire highway structure in the transform domain under the FWD load is derived by combining the boundary conditions.The Laplace-Hankel inverse transform is utilized to obtain the numerical solution of the vibration response in the space-time domain.The effects of FWD load frequency and subgrade saturation on the vibration response and the correlation between subgrade performance deterioration and pavement surface vibration signals under FWD load are analyzed.It is found that the vertical dynamic displacement of the pavement surface is mainly influenced by the low frequency component of FWD load and increases with the increase of saturation.The vertical dynamic displacement of the pavement surface is more sensitive to subgrade performance deterioration than the vibration velocity of the pavement surface and the vertical dynamic stress of the subgrade surface.Moreover,the change rate of vertical dynamic displacement of the pavement surface at 1.2 m from the load center reaches the maximum.The results of the study can provide a scientific basis for selecting feedback indicators and locations of subgrade performance deterioration.
作者
张晶
杨吉红
卢正
唐楚轩
刘杰
ZHANG Jing;YANG Ji-hong;LU Zheng;TANG Chu-xuan;LIU Jie(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Hubei Jiaotou Wutian Expressway Co.Ltd.,Tianmen,Hubei 431701,China;Hubei Key Laboratory of Geo-Environmental Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;Xinjiang Transportation Planning Survey and Design Institute Co.,Ltd.,Urumqi,Xinjiang 830006,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2023年第S01期678-686,共9页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.42077261,No.42077262)。
关键词
FWD
非饱和路基
回弹模量
位移响应
路基劣化
FWD
unsaturated subgrade
resilient modulus
displacement response
subgrade deterioration
