基于温度场的BRT沥青路面结构永久变形特性分析

The Permanent Deformation Characteristics of BRT Asphalt Pavement Structure Based on Temperature Field

为揭示BRT沥青路面结构在温度场和公交车移动荷载联合作用下的永久变形特性,依托兰州BRT沥青路面工程,采用数值模拟方法建立沥青路面结构力学分析模型,通过Fortran语言编写用户子程序,引入夏季BRT道路实际温度场,研究了夏季BRT重复荷载作用下温度场与车速对路面结构永久变形的影响,并解释了其作用机理。结果表明,夏季BRT沥青路面结构易发生失稳性车辙;相较于BRT车辆作用的频次,温度对沥青路面永久变形的影响更大;上、中、下面层的凹陷和隆起变形均随车辆速度的增大而减小,且不同行车速度下,中面层的变形值大于上面层和下面层,为延缓BRT沥青路面结构永久变形的产生和发展,应在合理提高公交车车速的同时,重点关注中面层的抗变形能力,并加强面层之间的黏结力。

To reveal the permanent deformation characteristics of BRT asphalt pavement structure under the combined effect of temperature field and moving load of bus,taking for example the BRT asphalt pavement engineering in Lanzhou,the mechanical analysis models of asphalt pavement structure were established by using the numerical simulation methods.Through user subroutines programmed by Fortran language,the actual temperature field of BRT road in summer was introduced to research the influence of temperature field and vehicle speed on permanent deformation of pavement structure under repeated loads in summer,also the mechanism of action was explained.The research results indicate that the BRT asphalt pavement structure is prone to unstable rutting in summer.Compared with the frequency of BRT vehicles,temperature has a greater influence on the permanent deformation of asphalt pavement.Both of depression and uplift deformation of the upper,middle and lower surface layer decrease with the increase of vehicle speed,and the deformation value of the middle surface layer is greater than the upper and lower surface layer at different driving speeds.In order to delay the emergence and development of permanent deformation of BRT asphalt pavement structure,bus speed should be increased reasonably.At the same time,special attention should be paid to the deformation resistance of the middle surface layer and the strengthening of the bonding strength between the surface layers.