沥青路面影响因素及应力分析研究

发布时间：2018-06-12 22:17

本文选题：沥青稳定碎石 + 复合式基层　；参考：《西安工业大学》2017年硕士论文

【摘要】：半刚性基层沥青路面在过去很长一段时间内,被国内外广泛使用,但其容易产生反射裂缝,从而导致路面在使用前期就出现车辙、沉陷、疲劳开裂等破坏。为此,我国提出了复合式基层路面结构,即底基层为半刚性基层,上基层为沥青稳定碎石或级配碎石柔性基层。通过查阅大量文献表明,对于防止反射裂缝的发生,级配碎石复合式基层沥青路面的效果不及沥青稳定碎石的效果,同时,沥青混合料的模量直接影响路面的受力情况,故本文以沥青稳定碎石复合式基层沥青路面为研究对象,借助ABAQUS有限元软件,来分析各面层模量对路面应力的影响,为其进一步被广泛使用提供一定的指导作用。通过对路面力学模型的对比,确定出以时间硬化蠕变模型来模拟沥青混合料的蠕变特性,并将车轮作用荷载简化为矩形均布荷载,创建路面模型来进行应力分析,得出:当各面层模量增加时,竖向压应力和Mises屈服拉应力变小,而纵向剪应力变大;当上面层模量增大时,横向剪应力变大,但当中面层和下面层模量增加时,其变小。同时上面层模量对最大横向剪应力、最大纵向剪应力及最大Mises屈服拉应力的影响最大,中面层模量对最大竖向压应力的影响最大,故宜选择较低标号的沥青,如30#沥青、50#沥青,或者在沥青混合料中加入适量的高模量外加剂,来增加中面层的模量,从而降低其产生的竖向压应力,防止路面产生沉陷或车辙病害。另外为了减小拉应力,防止路面产生疲劳开裂,上面层宜采用骨架密实型级配类型或适当增加胶结料的含量,或者在较高温度下进行施工。最后,在检测沥青稳定碎石复合式基层沥青路面的最大竖向压应力、最大纵向剪应力及最大Mises屈服拉应力时,只需在任意一侧车轮的中心处取样检测即可,而检测最大横向剪应力时,只需在任意一侧车轮内侧取样即可。本文所研究内容对沥青稳定碎石复合式基层沥青路面的设计、施工和检测都提供了一定的理论依据,同时也对其增加使用寿命,减缓车辙、沉陷等破坏,增强服务性能和运营安全,降低养护和运营费用提供了非常好的指导意义。
[Abstract]:Semi-rigid base asphalt pavement has been widely used at home and abroad for a long time in the past, but it is easy to produce reflective cracks, which leads to rutting, subsidence, fatigue cracking and so on. Therefore, the pavement structure of compound base is put forward in our country, that is, the base is semi-rigid base, the base is asphalt stabilized macadam or graded macadam flexible base. By consulting a large number of documents, it is shown that the effect of graded crushed stone composite base asphalt pavement is not as good as that of asphalt stabilized macadam, and the modulus of asphalt mixture directly affects the stress of pavement. Therefore, this paper takes asphalt stabilized macadam composite base asphalt pavement as the research object, with the help of Abaqus finite element software, to analyze the influence of each surface layer modulus on pavement stress, and provide some guidance for its further wide use. Through the comparison of pavement mechanics model, the time hardening creep model is established to simulate the creep characteristics of asphalt mixture, and the wheel load is simplified to rectangular uniform load, and the pavement model is established to analyze the stress. It is concluded that the vertical compressive stress and Mises yield tensile stress become smaller and the longitudinal shear stress becomes larger when the modulus of each surface layer increases, while the transverse shear stress increases with the increase of the modulus of the upper layer, but decreases with the increase of the modulus of the middle layer and the lower layer. At the same time, the modulus of the upper layer has the greatest influence on the maximum transverse shear stress, the maximum longitudinal shear stress and the maximum Mises yield tensile stress, and the modulus of the middle layer has the greatest influence on the maximum vertical compressive stress. Therefore, the lower grade asphalt, such as 30# asphalt and 50# asphalt, should be chosen. Or adding appropriate amount of high modulus admixture to the asphalt mixture to increase the modulus of the middle surface layer so as to reduce the vertical compressive stress and prevent the road surface from subsidence or rutting disease. In addition, in order to reduce the tensile stress and prevent the fatigue cracking of the pavement, the upper layer should adopt the framework dense gradation type or increase the content of the binder properly, or carry on the construction under the higher temperature. Finally, in the detection of maximum vertical compressive stress, maximum longitudinal shear stress and maximum Mises yield tensile stress of asphalt pavement with asphalt stabilized macadam composite base, it is only necessary to sample and detect at the center of any wheel. When measuring the maximum transverse shear stress, it is only necessary to sample the inside of any side of the wheel. The content of this paper provides a certain theoretical basis for the design, construction and inspection of asphalt pavement with asphalt stabilized macadam compound base course, and at the same time, it also provides a certain theoretical basis for increasing its service life, slowing down rutting, subsidence, and so on. Enhance service performance and operational safety, reduce maintenance and operating costs to provide very good guidance.
【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U416.217

【参考文献】