考虑横观各向同性特性的沥青路面动力学分析

Dynamic Mechanical Analysis of Asphalt Pavement Based on Cross-isotropic Properties

考虑到沥青混合料、粒状类基层和土质路基等材料各向异性特性对沥青路面动力学的影响,基于对各国研究现状的综合分析,采用有限元数值分析方法,在弹性假设下引入横观各向同性系数,建立沥青路面三维有限元模型;采用ABAQUS进行DLOAD子程序二次开发,实现非均布竖向移动荷载的数值模拟;并给出移动荷载作用形式、边界条件和材料参数;而后对比分析了移动荷载作用下各向同性和不同横观各向同性特性条件下三向应变场的差异。结果表明:当考虑横观各向同性特性时,目前采用的设计标准偏于危险,基于各向同性特性的路面设计低估了与永久变形和疲劳裂缝相关的应变。

Considering the effect of anisotropic properties of asphalt mixture, aggregate base and soil subgrade on the asphalt pavement and based on comprehensive studies at home and abroad, the finite element numerical analysis and cross-isotropic coefficient under the assumption of linear elastic layer were introduced to establish a 3D pavement structure model. By using the finite element software ABAQUS, subroutine DLOAD was further developed to simulate a vertical moving load with non-uniform distribution. The moving load action, boundary condition and material parameters were given. And the comparative analysis of the differences of vertical, longitudinal and transverse strains of the moving load under isotropic and cross-isotropic conditions was carried out. The results show that when considering the cross-isotropic behavior of asphalt pavement, the currently-adopted design standard is comparably insecure and the pavement design based on isotropic elasticity underestimates the strains related to permanent deformation and fatigue cracking failure.