沥青混凝土路面结构蠕变损伤研究

发布时间：2018-05-08 11:18

本文选题：沥青混合料 + 修正Burgers蠕变模型　；参考：《西安建筑科技大学》2015年硕士论文

【摘要】：沥青路面以其良好的性能在道路建设中得到广泛的应用,虽然它有很多的优点,但是在路面的施工阶段,投入使用阶段以及维护过程中都会产生不同程度的损伤,随着这些损伤的不断累积,路面结构内部的裂化程度越来越严重,从而导致路面结构的承载力减小,加速路面结构破坏,减少其剩余使用寿命,在一定程度上为国家造成了损失,所以很有必要搞清楚损伤的演化过程以及损伤对其内力和变形产生的影响。本文在粘弹性理论和损伤力学的基础上,推导出了沥青混合料的蠕变损伤本构模型,并采用有限元软件ABAQUS建立三维模型,研究其在考虑损伤和无损伤两种状态下力学响应的变化。在此过程中,主要解决的问题是损伤变量形式如何确定,如何将损伤场耦合到无损材料的本构关系中,从而得到蠕变损伤本构模型。综上,本文对下面几个方面展开了研究并得到有关结论:(1)运用连续介质损伤力学理论和应变等价原理,确定出能够反映沥青混合料变形的损伤变量,从而推导出蠕变损伤本构模型的本构方程。(2)根据ABAQUS用户手册,用FORTRAN语言二次开发出蠕变损伤模型的用户材料子程序UMAT,以便后续进行有限元分析。(3)验证该蠕变损伤模型及UMAT子程序的准确性,应用有限元数值分析法,通过UMAT子程序的接口将蠕变损伤本构导入ABAQUS主程序,建立试验模块的三维有限元仿真模型,将损伤状态下的计算结果与单轴静载蠕变试验结果进行对比。(4)建立沥青路面的三维模型,对沥青路面在不同荷载和不同温度下进行有限元计算,研究其在有损伤和无损伤两种状态下的不同响应。从得到的计算云图和数值结果可知,无论是变换荷载还是温度,在不考虑损伤的情况下,等效蠕应变只出现两个阶段,即刚开始等效蠕应变随时间逐渐增大,之后几乎成水平线,呈现固结效应,这不符合实际情况,当考虑损伤时,应用本文建立的修正Burgers蠕变损伤模型结果曲线能够很好地模拟沥青混合料蠕变过程的三个阶段,且破坏时间随着荷载的增大和温度的升高越来越短,同时我们还发现损伤值与等效蠕应变、竖向位移存在一定的关系,并且通过Origin8.0拟合出精度比较高的关系式,为沥青混合料蠕变损伤的深入研究提供一些参考。
[Abstract]:Asphalt pavement has been widely used in road construction because of its good performance, although it has many advantages, but in the pavement construction stage, put into use stage and maintenance process will produce varying degrees of damage. With the continuous accumulation of these damages, the degree of cracking inside the pavement structure becomes more and more serious, which leads to the reduction of the bearing capacity of the pavement structure, the acceleration of the destruction of the pavement structure, and the reduction of its remaining service life. It is necessary to understand the evolution process of the damage and the influence of the damage on the internal force and deformation. On the basis of viscoelastic theory and damage mechanics, the creep damage constitutive model of asphalt mixture is derived, and the three-dimensional model is established by using finite element software ABAQUS. The change of mechanical response was studied under the condition of damage and non-damage. In this process, the main problem is how to determine the form of damage variables and how to couple the damage field into the constitutive relationship of lossless materials, and then obtain the creep damage constitutive model. In summary, the following aspects are studied in this paper, and the relevant conclusions are drawn: (1) using continuum damage mechanics theory and strain equivalence principle, the damage variables which can reflect the deformation of asphalt mixture are determined. Thus the constitutive equation of the creep damage constitutive model is derived. (2) according to the ABAQUS user manual, In order to verify the accuracy of the creep damage model and UMAT subroutine, the user material subprogram Umatt of creep damage model is developed by using FORTRAN language twice in order to verify the accuracy of the creep damage model and UMAT subprogram, and the finite element numerical analysis method is applied to verify the accuracy of the creep damage model. Through the interface of the UMAT subroutine, the creep damage constitutive model is introduced into the ABAQUS main program, and the three-dimensional finite element simulation model of the test module is established. Comparing the results of damage state with the results of uniaxial static creep test, the three-dimensional model of asphalt pavement is established, and the finite element calculation of asphalt pavement under different loads and temperatures is carried out. The different responses of the two states with and without damage were studied. From the calculated cloud diagram and numerical results, it can be seen that the equivalent vermicular strain has only two stages without considering the damage, that is, the equivalent vermicular strain increases gradually with time at the beginning, regardless of the change load or temperature. It is not in line with the actual situation. When damage is considered, the result curve of modified Burgers creep damage model established in this paper can well simulate the three stages of creep process of asphalt mixture. The damage time is shorter and shorter with the increase of load and temperature. At the same time, we also find that there is a certain relationship between the damage value and equivalent vermicular strain and vertical displacement. It provides some references for the further study of creep damage of asphalt mixture.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.2

【参考文献】