非匀速移动载荷刚性路面动力分析

 研究了变速交通荷载下的刚性路面动力。首先,刚性路面被认为是一个矩形的Pasternak地基的弹性支承阻尼正交各向异性板,这种假设,特别是对刚性的路面接头,其中一个可能会发现旋转和垂直剪切变形是十分适用的,矩形板块的边界具有提供垂直支撑和弹性转动约束的支承钢销和拉杆。其次,依据经典薄板理论,给出了平板的横向挠度满足的偏微分方程。由该微分方程,系统的自然频率和模式形状可以用两个超越方程求解。以一个谐变振幅集中载荷表示移动交通荷载,载荷沿路面具有可变的速度。路面的动态响应可以从正交性质的特征方程获得,冲击挠度的解析形式由特征方程的正交特性得到。数值算例结果表明,负载的速度和角频率影响刚性路面最大动态挠度,如果移动交通负载以临界速度行驶,路面的振幅将趋于无穷大,从而导致道路被破坏。用本文方法,通过使用叠加原理,也可以应用于多车道连续负载下的路面动力可靠性分析。

Dynamic Analysis of Rigid Pavement Under Variable Velocity Moving Loads

In this paper, the rigid roadway pavement under dynamic traffic loads with variable velocity is studied. The rigid roadway pavement is modeled as a rectangular damped orthotropic plate supported by elastic Pasternak foundation. The boundaries of the plate are the steel dowels and tie bars which provide the elastic vertical support and the rotational restraint. The natural frequencies and the modal shapes of the system are obtained through solving two transcendental equations, derived from the solution of two auxiliary Levy's type problems, known as the Modified Bolotin Method. The dynamic moving traffic load is expressed as a concentrated load of harmonically varying magnitude, moving straight along the plate with a variable velocity. The dynamic response of the plate is obtained by using the characteristic equation with orthogonal properties. The results of a numerical example show that the velocity and the angular frequency of the loads affect the maximum dynamic deflection of the rigid roadway pavement. It is also shown that a critical speed of the load exists. If the moving traffic load travels at the critical speed, the rectangular plate will suffer from a deflection of infinite amplitude. The present mathematical solution should be verified further with the results of experimental researches, especially, with respect to the determination of the forces in the steel connecting devices (dowels and tie bars) along the joints.