宽温度域内沥青路面结构响应规律分析

为研究较宽温度范围内的沥青路面结构实际响应行为,基于RIOHTrack足尺路面试验环道,以落锤式弯沉仪(FWD)作为试验荷载,选择半刚性基层沥青路面和全厚式沥青路面作为研究对象,对两种路面结构2017年全年的服役温度和结构响应进行同步跟踪观测,得到了宽温度域内沥青路面结构响应基本规律,建立了温度与弯沉、温度与应变、温度与应力之间的关系模型,分析了结构内部应变、应力沿深度方向的分布特征. 结果表明:温度对弯沉、应变和应力响应具有显著影响,随着季节变化,宽温度域内的沥青路面结构响应数值会出现以年为周期的循环交替变化,冬季时结构响应数值小、夏季时结构响应数值大；可采用指数函数模型描述温度与结构响应参数的相关关系,决定系数R²可达到0.95以上,相关性好；宽温度域内,温度变化除引起结构内部应变或应力数值的单调增减以外,还会改变应变方向. 在路面结构计算中,宜选择最不利季节时的温度验算沥青混凝土层的受力状态,以保证结构安全性.

Analysis on response behavior of asphalt pavement structure in wide temperature range

To study the actual response behavior of asphalt pavement structure in a wide temperature range, a semi-rigid base asphalt pavement and a full-thickness asphalt pavement were selected as research objects and Falling Weight Deflectometer (FWD) as test load based on the RIOHTrack full-scale test track, and the service temperature and structure response of the two kinds of pavement structures were observed synchronously in the year of 2017. The basic rule of asphalt pavement structure response in wide temperature range was obtained, the relationship models between temperature and deflection, temperature and strain, and temperature and stress were established, and the distribution characteristics of strain and stress along the depth direction of the structures were analyzed. Results show that temperature had significant effect on deflection, strain, and stress response. With seasonal variation, the response values of the asphalt pavement structures in wide temperature range changed alternately with annual cycle, and the values were small in winter and large in summer. Exponential function model can be used to describe the correlation between temperature and structural response parameters, and the decision coefficient R² could reach more than 0.95 with good correlation. Within the wide temperature range, in addition to the monotonous increase or decrease of the strain or stress values inside the structure, temperature variation could also change the strain direction. In pavement structure calculation, it is suggested to select temperature at the most unfavorable season to check the stress state of the asphalt concrete layer in order to ensure the safety of the structure.