三轴移动载荷对半刚性路面性能影响分析

为研究多轴车辆移动载荷对半刚性路面性能影响规律,针对半刚性路面的特点,依据弹性层状体系理论,将半刚性路面的沥青层、半刚性基层、半刚性底基层及土基层按线弹性考虑,建立了半刚性路面的三维有限元分析模型,分析了车辆三轴移动载荷对半刚性路面性能影响。结果表明,3轴载荷作用下路面应力变化与车辆轴数有关,当车桥依次驶过路面时,路面应力出现3次突变,沥青层三向压应力、半刚性基层和底基层的垂直压应力、横向拉应力和水平拉应力均增大,最大拉应力出现在半刚性基层和底基层结合处;前轴驶过时轮迹带中心区域各层的横向剪应力最大,后轴驶过时轮迹带边缘区域各层的横向剪应力最大,最大值出现在沥青层底部;中轴驶过时路面各层的水平剪应力最大,最大值也出现在沥青层底部。因此,设计路面结构时,半刚性基层和半刚性底基层应选取抗弯和抗拉强度较高的材料,并应加强沥青面层的抗剪强度。

Analysis of the Performance of Half Rigid Road Under Three-Axle Vehicle Moving Loads

In order to study the performance of half rigid road under multi-axle vehicle moving loads, a 3 - D FEA model of half rigid road was established based on the elastic layered theory and the performance of half rigid road caused by three-axle vehicle moving loads was analyzed. The results indicated that the stress change of half rigid road was related to axle number due to three-axle vehicle moving loads. When the vehicle ran over half rigid road, there were three abrupt stress changes. Triaxial compressive stress of asphalt layer, vertical compressive stress, horizontal tensile stress and transverse tensile stress of half rigid base and subbase all increased. And the maximum tensile stress occurred at the bound between half rigid base and subbase. When the front axle ran over road, various layers of the center of wheel path bore the maximum transverse shear stress. But when the intermediate axle and rear axle ran over road, various layers of the edge of wheel path bore the maximum transverse shear stress, and the maximum transverse shear stress occurred at the bottom of asphalt layer. When the intermediate axle ran over road, the horizontal shear stress of various layers reached the maximum value, and as the maximum transverse shear stress, the maximum horizontal shear stress occurred at the bottom of asphalt layer. Hence, the materials should be chosen to strengthen the half rigid base and subbase, at the same time, improve the shear strength of asphalt layer on designing road.