横观各向同性黏弹性沥青路面的动力响应

Dynamic response of cross-anisotropic viscoelastic asphalt pavement

为了更好地表征路面在荷载作用下的力学行为,研究考虑基层和土基材料的横观各向同性特性的黏弹性沥青路面在落锤式弯沉仪(fal1ing weight deflectometer,FWD)荷载作用下的动力响应。从各向同性黏弹性和横观各向同性弹性轴对称空间动力问题的基本控制方程出发,借助相应的积分变换,分别建立积分变换域内的各向同性黏弹性体的双节点层单元刚度矩阵和横观各向同性弹性体的双节点与单节点层单元刚度矩阵,进而得到考虑横观各向同性的黏弹性多层沥青路面结构的解析刚度矩阵解。通过求解横观各向同性问题退化的各向同性问题,并与已有解答进行对比,验证本文计算方法的准确性。然后,分析基层和土基的横观各向同性特性对路表弯沉的影响。研究结果表明:随着基层和土基模量比减小,路表弯沉增大,且基层模量比变化的影响更显著。

In order to better characterize the mechanical behavior of the pavement under fal1ing weight deflectometer(FWD for short)load,the dynamic responses of viscoelastic asphalt pavement were analyzed considering the cross-anisotropy of unbound aggregates bases(UAB for short)and subgrades.Based on the governing equations for isotropic viscoelastic and cross-anisotropic elastic axisymmetric spatial dynamic problems,the stiffness matrixes in the integral transform domain of 2-noded layer element for the isotropic viscoelastic body and 2-noded and 1-noded layer elements for the cross-anisotropic elastic body were developed respectively,and then the analytical stiffness matrix solution of viscoelastic multi-layered asphalt pavement structure considering cross-anisotropy was proposed.The validity of the developed method was verified by comparing the results of cross-anisotropic problem reducing to isotropic problem with the existing solutions.Subsequently,the influences of cross-anisotropy of UAB and subgrade on the surface defections were investigated.The results show that surface defections increase with the decrease of modulus ratios of UAB and subgrades,and the ratios of modulus of UAB have more significant impacts.