柔性基层沥青路面结构对土基模量的要求

Requirement of Subgrade Modulus for Asphalt Pavement Structure with Flexible Base

基于ABAQUS有限元软件,建立了4种厚度的柔性基层沥青路面结构三维有限元模型,计算了半波正弦动载作用下,不同土基模量时路面结构的动态响应,分析了沥青层疲劳寿命和土基永久变形寿命随土基模量的变化规律和相互协调性问题。研究表明:土基永久变形预估寿命随土基模量的增大而显著增大,而沥青层疲劳预估寿命受土基模量变化的影响较小;柔性基层沥青路面结构在土基模量较小时,路面损坏类型由土基顶面永久变形控制,而当土基模量较大时,变为由沥青层疲劳损坏控制;进一步确定了路面控制损坏类型变化时的临界土基模量,提出了满足不同交通等级时的土基模量范围,为柔性基层沥青路面结构设计提供参考。

Based on ABAQUS software, 3D finite element models simulating flexible pavement structures with four different thicknesses were established. The dynamic responses of flexible pavement structures varied with subgrade moduli under half-sinusoidal load were calculated. Both the fatigue life of asphalt layer and the permanent deformation life of subgrade were analyzed, and their coordination effect was studied as well. The results indicate that the permanent deformation life of subgrade increases with subgrade modulus. However, the fatigue life of asphalt layer is less affected by the variation of subgrade modulus. The type of structural failure of flexible pavement is determined by excessive permanent deformation at the top of subgrade when the subgrade modulus is small, while the type of structural failure turns to be the fatigue life of asphalt layer as the subgrade modulus increases. Furthermore, the critical subgrade modulus while the type of structural failure varies is determined, and the range of subgrade modulus which meets various traffic levels is presented to provide reference for the design of flexible pavement.