动载作用下典型沥青路面剪应力特性分析

Analysis on Shear Stress Property of Typical Asphalt Pavement under Dynamic Load

为探究动态荷载作用下沥青路面的剪应力响应特征,应用ABAQUS建立半刚性路面(S1)、倒装式路面(S2)、组合式路面(S3)的动力有限元分析模型,针对3类典型沥青路面的剪应力空间分布特性,动、静剪应力差异以及路面结构和车辆荷载参数对剪应力的影响规律等方面开展数值模拟分析。研究结果表明:沿路面深度方向,剪应力最大值位于中面层顶面位置(40 mm深度处);剪应力在水平面的分布主要集中在车轮荷载作用区域,最大值位于轮印边缘位置处;S2的剪应力最大,S1与S3的剪应力较为接近,S3略大于S1;相比于静态荷载,动荷载作用下的剪应力更大,二者的差异性随轴重水平提高逐渐增大;剪应力随基层模量增加而减小,随面层模量的增大而增大,随基层厚度增加逐渐减小;随着车速和轴重的提高,路面剪应力均逐渐增大;剪应力随轴距增加呈先增大后减小的趋势,在轴距取1.1 m时,剪应力出现最大值;随着行车加速度的增加,路面剪应力基本呈线性关系增大,轴重与车速的提高,均会增大沥青路面在车辆制动过程中的剪应力。

In order to investigate the response characteristics of shear stress in asphalt pavement under dynamic load,the dynamic finite element analysis models about semi-rigid pavement（ S1）,inverted asphalt pavement（ S2）,and compound pavement（ S3） are established with ABAQUS. Some numerical simulations are conducted to study the spatial distribution characteristics of shear stress in the 3 kinds of typical asphalt pavement,the difference between dynamic and static shear stresses,and the influence of pavement structure and vehicle load parameters on shear stress. The result shows that（ 1） along the pavement depth,the maximum shear stress is at the top of mid-surface（ 40 mm depth）;（ 2） the distribution of the shear stresses in the horizontal plane is mainly concentrated in the wheel load area,and the maximum value is located at the edge of wheel impression;（ 3） the shear stress of S2 is the maximum,and the shear stresses of S1 and S3 is close,the shear stress of S3 is slightly large than that of S1;（ 4）compared with the static load,the shear stress under dynamic load is larger,and the difference between dynamic and static shear stresses gradually increases with the increase of axle load level;（ 5） the shearstress decreases with the increase of the base modulus,while it increases with the increase of the surface modulus,and also gradually decreases with the increase of base thickness;（ 6） the shear stress in pavement gradually decreases with the increase of vehicle speed and axle load;（ 7） the shear stress increases firstly and then decreases with the increase of wheelbase,and the shear stress achieves the maximum value when the wheelbase is 1. 1 m;（ 8） with the increase of the driving acceleration,the pavement shear stress generally increases in a linear way;（ 9） the shear stress of asphalt pavement increases with the increase of axle load and vehicle speed during braking.