基于ALF加速加载试验的沥青层疲劳损伤

Fatigue Damage in Asphalt Layer Based on ALF Accelerated Loading Test

为了得到沥青层疲劳损伤规律,根据北京ALF试验路疲劳性能加速加载试验,利用短周期单元的渐进疲劳损伤模拟模型,按照Miner法则进行先行累积,分析了加速加载过程中沥青层模量和沥青层底应变的变化规律。结果表明,重复荷载作用下,沥青层模量逐渐减小,而沥青层层底拉应变逐渐增大;在双对数坐标下,模量的衰减及应变与加载次数具有很好的线形相关性;沥青层越薄,温度对沥青层层底拉应变的影响越大,应变变化率与温度呈正比关系;在相同的荷载作用次数下,沥青层越薄,疲劳损伤率越大。

In order to find the regularity of fatigue damage of asphalt layer, according to the accelerated loading test of fatigue performance on Beijing ALF test road, the simulation model of short cycle unit gradual fatigue damage was adopted. The fatigue damage was cumulated by Miner theory, and the variation regularities of asphalt layer module and layer bottom tensile strain in the accelerated loading process were analyzed. The results show that （ 1 ） asphalt layer module gradually diminishes and tensile strain of asphalt layer bottom gradually increases ; （2） strain and attenuation of module have good linear relativity with loading in double logarithm coordinate system; （3） the thinner the asphalt layer, the greater the influence of temperature on tensile strain at bottom of asphalt layer, and strain variety ratio is in direct proportion to temperature; （4） under the same loading cycles, the thinner the asphalt layer, the greater the fatigue damage ratio.