低速与变速动载作用下沥青路面动力响应

Dynamic response of asphalt pavement under moving loads with low and variable speed

为分析低速、变速车辆动载对沥青路面结构的影响,利用室内动态模量实验结合时温等效原理确定几种路面沥青材料的动态模量主曲线;通过调查和计算得到车辆在不同变速条件下的荷载作用方式;建立车辆连续变速条件下路面材料动态模量的变化规律;利用三维有限元模型分析不同车速和速度变化对沥青路面力学响应的影响,比较采用动态模量和抗压回弹模量的计算结果。实验结果表明:动态模量能较好地反映车辆荷载作用下的路面材料力学性能,较低车速更易导致路面结构的疲劳损伤,而车辆加速度的增加使结构面层内剪应力峰值增长较大,易导致车辙、拥包等剪切破坏。

In order to study the influence of vehicle loads with low and variable speed onasphalt pavement, the dynamic modulus master curves of several asphalt mixtures were determined according to the laboratory test data and time-temperature superposition principle. The moving load model was established by investigation and calculation. The change law of pavement materials＇ dynamic modulus under vehicles＇ variable motion was established. The influences of different vehicle speed and speed variation on the dynamic response were analyzed using 3D finite element method. The contrasts of numerical computation result between using dynamic modulus and compressive resilient modulus were also studied. The results show that dynamic modulus reflects mixture properties more accurately under moving loads, and the lower vehicle speed can cause fatigue damage more easily. The maximal horizontal shear stress increases greatly with the increase of vehicle acceleration, which makes swell and rut occur frequently.