刚柔复合路面动力响应模型的建立及其应用

研究生：侯芸

指导教师：郭忠印教授

二〇〇二年十二月

摘要

本文在汇总分析国内外关于复合结构和动力学现有研究成果的基础上，充分考虑不同车辆、地基、路面结构模型的前提下，建立复合路面结构响应的动力学模型。并应用三维有限元动力学的基本原理，结合Newmark积分方法逐步求解了运动方程。

以FWD动力荷载下柔性多层体系为例，讨论荷载周期对动态变形的影响，并研究移动荷载下温克勒地基上板的参数对变形和应力的影响。在充分了解动力荷载对路面结构作用机理的前提下，详细研究材料参数、脱空、支承、土工材料对复合结构变形、应力响应的影响。提出了应用沥青层底拉应变作为沥青混凝土厚度设计的控制标准，并应在设计时验算表面拉应变，层间水平剪应变的方法。考虑参数对模型变形应力的影响，初步确定材料参数的适宜范围，并通过理论分析，给出铺设土工材料的适宜长度和最小拉伸模量。

结合山东某高速公路的FWD实测结果和室内的复合结构疲劳试验的结果，对复合结构模型的可靠性和计算精确度进行验证。在室内外的研究成果的基础上，分析考虑动力模型在实践中的应用问题，对复合结构的设计方法作了构想，并提出以弯沉盆形态进行路面结构判断的方法。

关键词：刚柔复合路面，三维有限元分析方法，Newmark积分，Fwd荷载，动态弯沉盆形态，土木料

ABSTRACT

On the base of  research result on current stiff-flexible bonding pavement and dynamics field，the paper throughly analyse  model of subgrage，vehicle and pavement structure．Then the tiff-flexible bonding pavement model is  built．Dynamic  response of pavements subjected to dynamic loads is analyzed by using the  three-dimensional (3D) finite-element method in conjunction with Newmark  integration scheme．

By the example  of layered pavements subjected to FWD load，the effect of periodic time of load on dynamic  deflection is given．And dynamic response of rectangular plates on viscoelastic  foundation layered pavements subjected to moving point loads is analyzed．Natural frequency and  critical speed are gained．The variations of the calculated value of deflection and tensile  stress depending on the moving speed，physical parameter of plate and subgrade are given．

The present  results arc compared with the available theoretical result to validate the  accuracy of the present algorithm．A study is conducted to evaluate the effects of various parameters  on the dynamic response of layered pavements subjected to dynamic loads．

Basing on the  thorough understanding of the interactive acting mechanism between load and  pavement structure，the influences of materials characters，local instability，surport，geosynthetics on  stiff-flexible bonding pavement’s strain and stress response had fully been conducted．The surface tension stress of  thin asphalt concrete on rigid pavement with crack is needed to check and the  bottom tension stress of asphalt concrete must be calculated in the design of  pavement．According  to the contribution of index on deflection and stress，the suitable parameters is  given．The effect  of length and modulus of interlayer on dynamic response is taken account．According to the theory study，the least length and modulus  of interlayer is suggested．

In addition，to illustrate accuracy of  theory results and confidence level of model，test sites was test by Fwd device in Shan—dong Province and fatigue  test of stiff-flexible bonding pavement was implemented．On the base of research  results，application  of dynamic model of stiff-flexible bonding pavement is illustrated．The design methods of  stiff-flexible bonding pavement was considered，and methods of identification stiffness of  pavement Was recommended by shape of deflection basins．

Keywords：stiff-flexible bonding  pavement，three-dimensional  (3D) finite-element method，Newmark integration，FWD load，shape of dynamic deflection basins，geosynthetics