沥青混合料车辙变形的计算机模拟

【作者】 张浩然；

【导师】 延西利；

【作者基本信息】 长安大学 ， 道路与铁道工程， 2003， 硕士

【摘要】 在车辆荷载的反复作用下，高温时产生的永久变形和车辙是沥青路面的典型破环特征。由于交通量的不断增长、交通荷载的增大、渠化交通道路长度的飞速增长，致使道路在较短时间内产生车辙的情况越来越多，因而有必要进行进一步的研究。 车辙试验较好地模拟现场应力状态、简单实用，车辙试验的变形量和动稳定度值逐渐成为抗车辙能力的重要标准。但车辙试验存在缺点，不能获得材料基本力学参数、不能预估车辙变形发展。 本文将粘弹性理论和人工神经元网络应用于车辙试验动稳定度的预估。本文应用粘弹性理论研究车辙试验，应用粘弹性模型模拟车辙试验的试件，拟合车辙试验的轮载，带入粘弹性本构方程，获得理论解，从而获得车辙试验的变形曲线和动稳定度值。通过对车辙试验变形曲线的拓展，预估车辙试验变形的发展趋势。本文应用BP人工神经元网络，建立沥青混合料的矿料通过百分率、沥青用量、毛体积密度、空隙率、试验温度与沥青混合料粘弹性参数的关系，或建立沥青混合料的矿料通过百分率、沥青用量、毛体积密度、空隙率、试验温度与车辙试验动稳定度值的关系，从而预估车辙试验的动稳定度值和绘制车辙试验变形曲线。 在本文的基础上，编制了车辙试验动稳定度预估和绘制车辙试验变形曲线的程序。应用该程序可方便地预估动稳定度值，获得车辙试验变形曲线，进而估计车辙变形发展趋势。该程序亦可为车辙试验提供参考。它可用于粗略进行沥青混合料级配的选择工作，在进行沥青混合料配合比设计工作时节省一定的时间。更多还原

【Abstract】 At the effect of repeat traffic loading, the permanent deformation by hot weather and rutting is typical symptoms of asphalt pavement damage. Since the traffic volume is increasing continuously, the weight of vehicle loading is increasing gradually and the length of traffic channelled highway is increasing rapidly, the status of severe rutting in short time arises frequently. For this reason, it is necessary for us to carry out further research.The wheel tracking test perfectly simulate the field stress status, simple and applicable. The deformation and DS(Dynamic Stability) of the wheel tacking test are becoming the criterion of rutting resistance. However, the wheel tracking test has its demerit, because we cannot get the basic mechanics parameter and estimate the evolution of the deformation.In the paper, viscoelastic theory and ANN(Artificial Neural Network) are applied to estimate DS and draw the curve of deformation. Viscoelastic theory is applied in wheel tracking test. The specimen of the test was stimulated by viscoelastic model and the wheel load was stimulated by special function, which are brought into viscoelastic equation. After solving the equation, we can work out the theoretical answer. Thus we can figure out the DS and the deformation curve. By prolonging the deformation curve, we can estimate the tendency of deformation. In the paper, by using BP(Back Propagation) method of ANN, we can get the relationship between grading, asphalt-aggregate ratio, bulk density, percentage of voids, test temperature and DS. At the same time, we can get the relationship between grading, asphalt-aggregate ratio, bulk density, percentage of voids, test temperature and viscoelastic parameter. At last, we can estimate the DS and draw the deformation curve.On the basis of the paper, we write a program to estimate DS and draw deformation curve. Using this program, we can estimate DS and draw deformation curve conveniently. Moreover, we can estimate the tendency of the curve evolution. This program can also be a reference to the asphalt mixture grading design. It can help in selecting grading roughly and saveing time in asphalt mixture design.更多还原