典型沥青路面动态应变响应特性及疲劳寿命分析

Analysis on Dynamic Strain Characteristics and Fatigue Life for Typical Asphalt Pavement

针对半刚性路面(S1)、倒装式路面(S2)、组合式路面(S3)开展三维有限元计算,分析其面层底动态应变的空间分布特性及车辆荷载参数对沥青路面动态应变响应的影响规律;同时,基于应变响应及沥青层疲劳预估方程,对比不同类型路面的疲劳寿命.结果表明:行车荷载在沥青路面面层层底平面所引起的拉应变主要集中在轮印作用区域,其由应变值所表征的最不利位置出现在轮印面积中心;车辆动载条件下的应变响应量小于静态荷载模式,其中,S2的动、静力差异性表现尤为显著;随着轴质量的增加,面层底动态应变逐渐增大;而随着车速的提高,应变响应量逐渐减小;随着轴质量的增加,沥青层疲劳寿命急剧减小;在行车安全的前提下,合理提高车辆行车速度有利于提高沥青路面使用寿命,3种路面的面层疲劳寿命排序为S1>S3>S2.

The three-dimensional finite element analysis on the asphalt pavement with semi-rigid base（S1）,the inverted asphalt pavement structure（S2）,and the compound asphalt pavement（S3）were carried out to study the spatial distribution characteristics of dynamic strain at the bottom of asphalt surface layer,and the influence of vehicle load parameters on dynamic strain.According to the fatigue prediction equations,the comparison of fatigue life for different types of pavement based on strain response was presented.The results show that the strain response caused by traffic load at the bottom of the surface layer is mainly concentrated in the wheel printing area.The most unfavorable position of the tensile strain at the bottom of the surface layer locates in the center of the wheel load.The strain response under dynamic load is less than that the static one.The strain difference between the dynamic and static loads is significant in S2.With the increase of axle load,the strain at the bottom of the surface layer increases;with the increase of driving speed,the strain decreases generally;with the increase of axle load,the fatigue life of asphalt layer decreases sharply.On condition of traffic safety,high speed extends the service life of asphalt pavement.The surface layer fatigue life of the 3vement is sorted：S1〉S3〉S2.