考虑沥青路面材料参数空间差异性的解析计算及影响分析

Under the influence of the environment and loads, pavement materials exhibit modulus gradients, imperfect contact conditions, and transverse isotropies. These characteristics are termed as spatial differences in material parameters. Moreover, it is critical to establish an analytical solution for the response analysis and structural design approach considering the spatial differences in asphalt pavements. For this purpose, based on the fundamental equations of elastic mechanics, the integral transformation and state-space approach were adopted in the derivation of the general solution of transversely isotropic elastic layered media with exponential modulus gradient. Then, based on the wave propagation approach, the state vector was transformed into a wave vector, and the boundary conditions and interlayer conditions were employed to establish the analytical solution of the multi-layered pavement structure considering the spatial difference of material parameters. Subsequently, the corresponding software was compiled using the MATLAB platform. The accuracy and efficiency of this analytical solution were verified by means of the reference, BISAR program, and finite element software ABAQUS. Finally, based on typical numerical examples, the application of the analytical solution in the top-down crack and traditional fatigue damage analysis of asphalt pavements was illustrated. The theoretical derivation and results of the numerical examples reveal that the proposed analytical solution does not rely on stress functions, and the influence of large exponential functions on the solution accuracy can be avoided with the help of the wave propagation approach. Meanwhile, the proposed solution can facilitate the description of the boundary conditions and different interlayer conditions. The spatial difference of the material parameters in asphalt pavements cannot be ignored, and the continuous modulus gradient of asphalt pavements will result in higher surface tension and maximum shear stress in the pavement surface, thus aggravating the top-down cracking in asphalt pavements. Additionally, there is a coupling effect between the transverse isotropy and contact state between the layers, which intensifies the fatigue damage of the asphalt pavement.