重载沥青路面结构设计轴载及力学响应分析

Axle Load Design and Mechanical Response Analysis on Heavy-duty Asphalt Pavement Structure

为了探究重载沥青路面结构设计轴载参数及力学响应分析,基于鲁中地区的高速公路实测车辆轴载数据,分析其轴载谱确定本地区的沥青路面结构设计轴载参数,拟定2种沥青路面结构及计算模型参数,利用麦路(M-Pave)软件计算在135 kN和100 kN轴载水平下路面结构的剪应力和水稳层层底拉应力并进行结构寿命预估。结果表明:确定以单轴双轮胎135 kN作为本地区重载交通设计代表轴载。结构1的剪应力峰值出现在距路表深度1~2 cm处,结构2的剪应力峰值出现在路表下2~4 cm处。2种轴载水平下剪应力随距路表深度的变化趋势基本一致,随着深度的增加,剪应力逐渐减小。2种路面结构剪应力计算表现为在路表下0~12 cm深度范围内剪应力值为140~280 kPa,在12~30 cm深度范围内剪应力值为50~140 kPa,其中设计代表轴载135 kN下的最大剪应力比标准轴载100 kN下最大剪应力增加15%~16%。在相同轴载水平下,结构2的水稳层底拉应力较结构1增加约10%。在相同路面结构下,设计代表轴载135 kN下的水稳层底拉应力比标准轴载100 kN增加约34%。当交通量达到重、特重交通荷载等级时,不同轴载水平下2种结构的水稳层结构寿命均超过了40 a,其中结构2的沥青层寿命可达到18~34 a,结构1的沥青层永久变形寿命为10~23 a。

To explore the axle load parameters and mechanical response analysis on heavy-duty asphalt pavement structure design,based on the measured expressway vehicle axle load data in the central Shandong region,the axle load spectrum was analyzed to determine the axle load parameters of asphalt pavement structure design in this region.Two types of asphalt pavement structures and calculation model parameters were formulated.The shear stress and tensile stress of water stable layer bottom of pavement structure were calculated by using M-Pave software at 135 kN and 100 kN axle load levels,and the structural life was estimated.The result indicates that 135 kN single axle dual tire is determined as the representative axle load for heavy-duty traffic design in this region.The peak shear stress of structure 1 occurs at 1-2 cm depth from road surface,while the peak shear stress of structure 2 occurs at 2-4 cm depth below road surface.The shear stress variation trend with depth from road surface under 2 different axle loads is basically consistent.The shear stress gradually decreases with the depth increasing.The shear stress calculation for 2 types of pavement structures shows that the shear stress values are 140-280 kPa within the depth range of 0-12 cm below road surface;the shear stress values are 50-140 kPa within the depth range of 12-30 cm below road surface.The maximum shear stresses under the design representative axle load of 135 kN increase by 15%-16%compared with the maximum shear stress under the standard axle load of 100 kN.Under the same axial load,the tensile stress at water stable layer bottom of structure 2 increases by about 10%compared with structure 1.With the same pavement structure,the tensile stress at water stable layer bottom under the design representative axle load of 135 kN increases by about 34%compared with the standard axle load of 100 kN.When the traffic volume reaches the level of heavy and extra heavy traffic loads,the service lives of water stable layer structures of both structures under different axle loads exceed 40 years.The service life of asphalt layer of structure 2 can reach 18-34 years,and the permanent deformation service life of asphalt layer of structure 1 is 10-23 years.