沥青路面动应变响应及其动荷载作用等效换算

Dynamic strain response of asphalt pavement and equivalent conversion of load effects

通过现场动态实测试验,获取了在FWD冲击荷载与BZZ-100标准行车荷载作用下沥青面层底部的应变响应特征及其温度敏感性,研究了FWD冲击荷载与标准行车荷载作用间的等效换算关系。研究表明:在动荷载作用下,沥青面层底部主要呈受拉状态,其纵向应变响应大于横向应变;应变响应量随FWD荷载增大而增大,随行车荷载车速增大而减小;面层层底应变响应的温度敏感性主要与路面结构组合有关,受荷载变化的影响较小;面层底应变响应的温度敏感性排序为:倒装式路面S2>组合式路面S3>半刚性路面S1;随着FWD荷载增大,与其等效的行车荷载所对应的车速水平逐渐降低;在相同FWD荷载下,不同类型路面对应的等效行车荷载速度水平为:S1>S3>S2;建立了FWD荷载与标准行车荷载间的等效换算关系,有助于FWD荷载更准确地模拟实际行车荷载。

Full-scale field tests were conducted to analyze the measured dynamic strain response of asphalt pavement subjected to the falling weight deflectometer （FWD） load and BZZ-100 standard vehicle loading. The corresponding linkage between FWD load and BZZ-100 vehicle load was studied on the basis of strain equivalency. Results show that under the FWD load impact and various standard speeds , the longitudinal strain at the bottom of asphalt surface course is larger than that of the transverse strain; the dynamic strain increases gradually with increasing FWD load and pavement temperature. Furthermore, the temperature dependence of strain response is highly affected by the pavement structure, but it is little affected by the variation of FWD load. Under the influence of moving load, sensitivity of three types of pavement structures to pavement temperature is ranked as： S2 〉 S3 〉 S1. With the increase of FWD load, the speed of standard axle load based on strain equivalency decreases gradually; under the same FWD load, the corresponding speed of BZZ-100 standard axle load in S1 is the highest, followed by S3, S2. Results in this study reveal that the established equivalent conversion relationship between FWD load level and BZZ-100 vehicle speed is able to accurately simulate the actual traffic loads.