采用离散元法分析路面结构的疲劳特征

为了在考虑疲劳损伤和恢复性能的基础上,获取路面结构在重复荷载作用下的疲劳特征,采用离散元方法建立了路面结构模型,并分析了在正弦重复荷载作用下路面结构沥青层底部的受力特性.由于路面荷载的随机性,分别以荷载大小、荷载间歇时间、荷载作用次序为考察对象,分析其对路面结构沥青层底受力特征的影响.研究结果表明:随着周期荷载作用次数的增大,沥青层底部拉应力快速增大至某一基础值,并在此基础值附近呈周期性波动,拉应变则在以一定幅值波动的同时,呈现整体水平先急剧增大后缓慢增大的规律;延长荷载作用的间歇时间,虽然一定程度上增大了拉应力和拉应变的波动幅值,但却显著降低了沥青层底拉应力和拉应变的整体水平;不同的荷载作用次序在沥青层底引起的应力应变状态不同,从小至大序列的荷载对沥青层造成的损伤明显小于从大至小序列的荷载.

Research on Fatigue Performance of Asphalt Pavement under Repeated Load Based on Discrete Element

In order to research on the fatigue performance of asphalt pavement under repeated load considering the fatigue damage and healing of asphalt mixtures, the discrete element model of asphalt pavement was used to calculate the tensile stress and strain at the bottom of the asphalt layer. Considering the random dynamic loads of vehicle, the influence of load magnitude, rest period of repeated load and loading sequence was studied on fatigue performance of the asphalt layer. The results show that the tensile stress and strain at the bottom of the asphalt layer fluctuates according to the repeated load. The amplitude and level of stress or strain are in a linear proportion to load magnitude. With the increase of rest period of repeated load, the level of stress or strain at the bottom of the asphalt layer is reduced evidently and the amplitude of stress or strain is increased with a certain extent. The different fatigue performances of the asphalt layer are caused by different loading sequences. The fatigue damage of asphalt pavement by the sequence from heavy load to light load is more fearful than that by the sequence from light load to heavy load.