沥青路面永久变形预估研究

为了精确预估沥青路面的永久变形,以十天高速公路陕西汉中段为试验路段,通过实地观测统计获得了全年路面温度区间分布频率和全年不同温度区间的轴载等级分布频率,采用有限元建模并计算路面结构的偏应力,计算表明,偏应力随深度的增加呈先增大后减小趋势,且路面的中面层偏应力最大.通过不同温度及偏应力的三轴重复荷载试验,建立了SMA-13,AC-20,ATB-30沥青路面重复荷载永久变形黏弹性力学模型,其拟合相关系数大于0.980 0.综合考虑路面温度、路面厚度、荷载作用次数、荷载大小、路面结构中各点偏应力及沥青混合料蠕变柔量等因素,提出了沥青路面永久变形预估方法,试验表明,该预估方法可模拟沥青路面结构实际受力状态,准确预估其容许永久变形寿命.经计算,十天高速公路陕西汉中段的容许永久变形寿命为13a.

Permanent Deformation Prediction of Asphalt Pavement

In order to predict accurately permanent deformation of asphalt pavement, relying on Shiyan Tianshui Highway of Hanzhong section in Shaanxi,distribution frequency of annual pavement temperature range and axle load level in different temperature range were calculated, which are introduced into the process that is the finite element modeling calculation of partial stress of pavement structure. the deviatoric stress curve increases at first and gradually decay with the increase of depth, the maximum deviator stress appears in the surface layer.Through triaxial repeated load test at different temperature and partial stress, viscoelastic mechanics model of SMA 13, AC 20, ATB 30 three kinds of asphalt mixture were derived, the correlation coefficient is larger than 0.98. A new kind of asphalt pavement permanent deformation prediction method was put forward based on linear superposition theory considering temperature of pavement, pavement depth, loading times, load magnitude, the deviatoric stress of each point in pavement structure and the creep compliance of asphalt mixture. According to the change of load times every year, permanent deformation of surface layer was calculated in those days and were accumulated year after year, Allowable permanent deformation life of Shiyan Tianshui Highway of Hanzhong section in Shaanxi is 13 years that was predicted accurately. The results show that this method can better simulate the actual stress state of pavement structure, and accurately predict allowable permanent deformation life, which provide a reference for permanent deformation prediction of asphalt pavement in the future study.