基于沥青路面结构力学行为的车辙深度控制标准

为了进一步规范沥青路面车辙深度的控制标准, 研究了车辙深度对路面结构的影响; 考虑车辙断面特征, 建立了车辆跨越车辙时的动荷载计算模型, 并以冲击系数量化了车辆对路面结构的冲击效应; 通过数值仿真研究了车辆荷载作用下路面结构的内部损伤, 探索了不同车辙深度下路面使用性能的衰减规律。研究结果表明: 车辙深度对路面结构的冲击效应不可忽视, 冲击系数随着车辙加深线性增加, 基于冲击效应的车辙深度应不大于11 mm; 沥青混合料层的最大拉应变位于上面层层底, 与车辙深度正相关, 中面层和下面层的拉应变与车辙深度负相关, 但应变水平显著低于上面层, 基于面层弯拉破坏的车辙深度应不大于15 mm; 最大剪应力出现在上面层层底, 随着车辙深度的增加缓慢增大; 车辙深度处于5~10 mm, 各面层的剪应力整体变化较小, 当其从10 mm增加到25 mm时, 上面层0~1 cm深度处的剪应力增加了14.5%, 增速明显超过中面层和下面层剪应力的减小速度, 基于面层剪切破坏的车辙深度应不大于10 mm; 车辙深度对无机结合料稳定层拉应力的影响不大; 车辙深度超过15 mm后应关注路基顶面压应变的变化, 防止路基出现大的变形。 

Control standards of rut depth based on mechanical behavior of asphalt pavement structure

In order to further regulate the control standards of rut depth of asphalt pavement, the influence of the rut depth on the pavement structure was studied. A dynamic load calculation model of vehicle crossing the rut was established based on considering the characteristics of rut cross section, and the vehicle impact effect on the pavement structure was quantified by impact factor. The inner damage of pavement structure was studied by numerical simulation, and the degradation laws of pavement performance at different rut depths were explored. Research result shows that the impact effect of rut depth on the pavement structure cannot be ignored. The impact factor increases linearly with rut depth, and the allowable rut depth considering the impact effect should not be greater than 11 mm. The maximum tensile strain of asphalt mixture layer appears at the bottom of the upper surface layer and is positively correlated with the rut depth. While the tensile strains of the middle surface layer and lower surface layer are negatively correlated with rut depth, and their strain levels are significantly lower than that of upper surface layer. The rut depth based on the surface layer flexural failure should be less than 15 mm. The maximum shear stress appears at the bottom of the upper layer and increases gradually with rut depth. When the rut depth is between 5-10 mm, the shear stress of each surface layer changes little. When the rut depth develops from 10 mm to 25 mm, the shear stress at 0-1 cm depth of the upper layer increases by 14.5%, which is obviously faster than the decreasing rate of shear stress of the middle layer and lower layer. Thus, the rut depth based on the surface layer shear failure should be less than 10 mm. The rut depth has little influence on the tensile stress of inorganic binder stable layer. When the rut depth exceeds 15 mm, the change of compression strain on the top of subgrade should be focused to prevent large deformation.