Analysis on Dynamic Response of Saturated Asphalt Pavement under Moving Vehicle Loads by 3D Finite Element Method

Asphalt pavement is a kind of porous medium which consists of solid,liquid and gas phases under the action of outside environment.The coupled hydro-mechanical action leads to the initial failure of asphalt pavement.To explore the dynamic response of asphalt pavement subjected to moving vehicle loads is the premise for understanding the structure behavior of asphalt pavement.First,regarding asphalt mixture as a media consists of solid and liquid phases in level one reasonable approximation,based on the porous media theory,a 3D finite element model of typical semi-rigid base asphalt concrete pavement under moving load was developed in the assumption that the asphalt pavement is saturated.Then,the variation of 3D strain and stress as well as 3D distribution of vertical stress of pavement under saturated condition and dry condition were comparatively analysed.The result indicates that(1) the characteristics of dynamic response of asphalt pavement with moving load under saturated condition and dry condition in surface course are different;(2) it is more likely to have structure damage such as fatigue cracking and permanent deformation when asphalt pavement is under saturated condition;(3) in asphalt pavement design,it is more reasonable to use flexural-tensile strain as the index than flexural-tensile stress.