车辆多轮动载作用下柔性路面动应力响应

Dynamic Stress Response of Flexible Pavement Under Multiple Wheel Dynamic Loads of Vehicle

为研究重型车辆多轮动荷载产生的柔性沥青路面应力特性,建立考虑黏弹性的柔性沥青路面三维有限元模型,分析重型车辆多轮随机动荷载和移动恒动荷载作用下柔性沥青路面动态应力响应。结果表明:在路面的确定位置,2种动荷载作用下沥青各层的各向应力变化规律基本一致,而每个车轮通过时各向应力变化规律不同,沥青下面层Sup25底面纵向和横向应力呈现拉应力状态,且大于沥青各层上面的各向拉、压应力;在车辆行驶区域,沥青层各点的各向拉应力和压应力最大值出现的位置及大小均不相同,随机动荷载作用下各点的各向拉应力和压应力最大值的变化幅度较大,分别大于和小于移动恒动荷载作用下各点的各向拉应力和压应力最大值;沥青层各层在随机动荷载作用下各向最大拉应力和最大压应力相对移动恒动荷载作用下各向最大拉应力和最大压应力分别增加1.63%~20.14%和2.13%~28.93%;在研究柔性沥青路面动态响应时,必须考虑路面不平度引起的车辆多轮动荷载及其随机变化的影响。

In order to investigate the stress properties of flexible asphalt pavement generated by the multiple wheel dynamic loads of the heavy vehicle,the finite element model of flexible asphalt pavement considering viscoelasticity was established.The dynamic stress response of flexible asphalt pavement was analyzed under the multiple wheel random dynamic loads and moving constant dynamic loads.The results show that the stress variations of each layer are basically the same in the specific position under two dynamic loads,and the stress variation in each direction is different when the wheels pass through.The longitudinal and transverse stresses of the bottom of Sup25 layer present tensile stress,which are greater than tensile and compressive stresses of other layers in all directions.In the whole pavement,the position and size of the maximum tensile and compressive stresses of each point of the asphalt layers in all directions are not the same.The amplitude variation of the maximum tensile and compressive stresses of each point is large under the random dynamic loads,greater or less than the maximum under the moving constant dynamic loads.Compared with the stresses under the moving constant dynamic loads,the maximum tensile and compressive stresses in three directions of each asphalt layer under therandom dynamic loads will increase by 1.63%-20.14% and 2.13%-28.93%.During the course of the research of the dynamic response of flexible pavement,the multiple wheel dynamic loads caused by pavement roughness and its random variations must be considered.