动荷载下饱水沥青路面黏弹性分析

为深入剖析沥青路面动水损坏机理,基于多孔介质理论,建立饱水沥青路面有限元模型,比较分析面层为弹性和黏弹性,以及面层饱水和表面层饱水的动力响应,并分析孔隙水压力峰值的发展规律和周期荷载对孔隙水压力的影响。结果表明,黏弹性面层的竖向变形和负孔隙水压力较大,正孔隙水压力较小,面层底部未出现水平拉应力;孔隙水压力峰值的大小及出现的位置发生改变,正、负孔隙水压力峰值出现的最终位置分别在底基层内和下面层内;与路面完全饱水相比,面层饱水和表面层饱水的竖向变形较大,面层饱水的面层层底的负孔隙水压力较大,而表面层饱水的表面层底负孔隙水压力较小;周期荷载的作用使孔隙水压力出现明显的周期性正、负交替,面层间的负孔隙水压力峰值变化率较基面层间的大。据此分析得出,面层特性对饱水沥青路面的动力响应有较大影响,面层饱水对基面层的损害严重,沥青路面的水损坏主要发生在面层的中下部。

Viscoelastic analysis of saturated asphalt pavement subjected to dynamic load

To analyze the mechanism of dynamic moisture damage of asphalt pavement,comparison and analysis of the dynamic elastic and viscoelastic responses of asphalt layer,between saturated asphalt layer and saturated surface layer,were conducted,and the variation of peak value of pore pressure and the effect of periodic load on pore pressure were analyzed using FEM.The results indicate the vertical deformation and the negative pore pressure increase,the horizontal tensile stress at the bottom of asphalt layer has no effect on the viscoelasticy of asphalt layer.The peak value of pore pressure and its corresponding location have obvious change,and the final location appears at the subgrade interior and asphalt layer interior for the peak value of positive and negative pore pressure,respectively.The vertical deformation increase for both saturated asphalt layer and saturated surface layer,and the negative pore pressure at the bottom of asphalt layer also increase for saturated asphalt layer,whereas the negative pore pressure at the bottom of surface layer decrease for saturated surface layer compared with the saturated pavement.It also shows that there exist a distinct periodicity alternation between positive and negative pore pressure during periodic loading,and the peak value of negative pore pressure between surface layer and lower asphalt layer decrease.The study suggests that the mechanical behavior of asphalt layer may considerably influence the dynamic response of saturated pavement,the saturated asphalt layer has remarkable damage on asphalt layer and base,and moisture damage of asphalt pavement mostly appears at middle and lower position of the asphalt layer.