重载条件下沥青路面结构复杂受力特征及力学响应研究

Research  of complex working state and mechenic responses of asphalt pavement under  heavy-duty conditions

研究生：钱国平

指导教师：郭忠印教授

二〇〇四年八月

摘要

近年来，随着经济建设的发展，我国的道路交通车辆状况发生了深刻的变化，重载交通成为主干线路上的普遍现象；在此情况下，出现了高等级道路沥青路面性能超常规衰减和早期损害的系列问题。而现有的路面结构力学计算模型与计算方法，无法对重载交通下沥青路面主要病害类型进行力学机理的全面描述和合理解释；对这一问题认识的不足，极大制约了该领域相关问题的深入研究。因此，研究建立重载条件下沥青路面结构受力特性及力学响应的理论模型及其数值实现方法，成为当前研究工作的当务之急。

论文首先在对现有资料整理和现场实际调查的基础上，总结了当前我国道路交通车辆的基本状况，分析了“重载”的含义和特点，提出了相应的代表性车型；选取重载交通典型路段进行路况调查，总结得到重载条件下沥青路面结构的主要损害类型。

其次，论文从车辆一路面系统力学作用的角度出发，进行了合理简化分解，提出从“车辆对路面的力学作用”和“路面结构力学响应”两方面，利用“车辆竖向振动荷载模型”、“轮胎．路表接触应力模型”以及“路面结构力学响应模型”三子系统模型来分析重载交通车辆对沥青路面结构的力学影响的研究技术思路，并对三个子系统模型分别进行如下研究：

①在对路面不平整度等因素合理简化的基础上，针对代表性车辆轴型，分别建立双自由度和三自由度车载振动模型；

②在总结前人研究成果基础上，提出不同车载状况下的轮胎．路面三向接触应力模型；

③基于弹性动力学的基本原理，利用坐标变换和多维Fourier变换技术，建立了能综合考虑动态(振动)、移动、非均布三向复杂受力的多层弹性层状体系理论通用力学响应模型以及数值实现方法。

然后，利用上述三个子系统模型，对不同车载状况下的沥青路面结构受力特性及力学响应进行了深入广泛计算，对比分析了重载交通车辆对沥青路面的力学影响：同时，对相关的车载系统参数(轴载、轴型与车型、车速、轮胎胎压等)及路面结构参量(面层模量、基层模量、结构组合等)进行敏感性分析。基于计算分析结果，给出了重载条件下沥青路面损害力学机理的合理解释，并提出相关建议。

针对基本理论模型及部分计算分析结论，论文最后部分进行了试验验证研究，证明本文理论分析成果的可靠性和准确性。

关键词：：重载条件，沥青路面，多层弹性体系，振动车载，轮胎一路表接触应力，动态移动，三向非均布荷载，多维傅立叶变换，力学响应。

ABSTRACT

In the past decades，great  change of vehicle characteristic on the road has taken place with the economy  development in our country．And  heavy-duty conditions have become the widespread phenomenon on the major  highway．All this change resulted in  such problems as irregular property degradation and earlier damage of asphalt  pavement．But existing calculation  models and methods for structure mechanics of pavement could not describe and  explain the mechanism of main defect type in the asphalt pavement under  heavy-duty conditions appropriately．Lack of  cognisance to these problems constricted more in•depth  research in this field．So，research on  the theory model and numerieal method of the working force behaviour and  mechanical responses of asphalt pavement structure becomes the urgent affairs．

Firstly，based on  the work of sorting relevant reference and investigation in the field，the basic  state of vehicles on the road in our country was concluded，and the  meaning and characteristics of “heavy—duty”were  analysed，then representative vehicle  type Was proposed in this thesis．Main defect  type was concluded after investigating the road condition of the typical road  sections under heavy-dutyconditions．

Secondly，the system  of vehicle•pavement Was simplified in  the view of mechanical function．The technical  line for researching the mechanical effects on the asphalt pavement structure  under heavy-duty conditions Was proposed，which used‘the model  of vibrating vehicle load’，‘the model  of tyre—pavement contact stress’，and‘the model  of mechanical response of pavement structure’．Some  studies were done on these models as follows：

①The vibrating vehicle  models of two—and three—degree of  freedom were constructed for the representative vehicle axle type based on  the reasonable simplified of some factors，such as  pavementroughness．

②The model of  three-direction contact stress between tyre and pavement under different  vehicle 10ads was developed based on the existing relevant theory．

③Based on  the theory of elastic dynamics，and  considering the dynamic，moving，and  non-uniformly distributed three-dimension working forces，the common  mechanical response model and numerical method of multiplayer elastic systems  were proposed using the techniques of coordinate transform and multi．dimension  Fourier transform．

Thirdly, based on the three  subsystem models mentioned above，the  mechanics working state and responses of asphalt pavement under different  vehicle load conditions were calculated accurately, then the mechanical  effects on asphalt pavement under heavy-duty conditions were analyzed．And the  sensitivity analysis of the parameters related to vehicle system and to  pavement structure Was implemented．Base on the  calculated results and analysed conclusions，the  mechanism of main defects in asphalt pavement under heavy—duty  conditions Was explained，and some advice Was  proposed．

Finally, the experimental studies  were implemented to validate the accuracy of the theory models and  reliability of partial calculated results．.

Key Words: Heavy—duty conditions, Asphalt pavement, Vibrating vehicle  load,  Multilayer  elastic systems, Tyre·pavement  contact stress,  Dynamic moving non—uniformly distributed three-dimensional load, Multi—dimensional  Fourier transform，Mechanics response.