机动安定定理在路面结构安定分析中的应用

Application of kinematic shakedown theorem in shakedown analysis of pavement structures

为了准确评价路面结构的承载能力,基于机动安定理论提出一种应用于路面结构的上限安定分析方法,计算分析荷载分布方式、路面厚度、路面材料内摩擦角及结构层间模量比对路面结构安定上限荷载影响,并与弹性极限、塑性极限及安定下限解进行对比分析.结果表明:单轮轴载下安定上限荷载随反映荷载的分布形式的a/r值增大而减小,双轮轴载下安定上限荷载随a/r值增大而增大;安定上限荷载随路面结构层厚度、材料内摩擦角增大而增大,并在面层厚度与荷载当量半径比h/r=2.5处开始趋于稳定;安定上限荷载随上下层弹性模量比E/E0的增加而减小,且在E/E0为1.0时安定上限荷载可取得最大值;路面结构安定上限荷载要大于弹性极限和安定下限荷载但小于塑性极限;安定上限荷载能较好地反映路面结构承载力,可为路面结构设计提供参考.

To accurately evaluate the bearing capacity of pavement structures,this paper proposed a upper shakedown analysis method based on the kinematic shakedown theorem,then calculated and analyzed the dependence of dimensionless upper shakedown load on the loading distribution,depth and angle of internal friction in the basecourse and ratio of elastic module in the basecourse and subgrade.Meanwhile the upper shakedown load was compared with elastic limit,plastic limit and lower shakedown load.The results showed that the upper shakedown load decreases with the increasing of a/r in a single-heel system,while increases in a dual-wheel system.The upper shakedown load increases with the increasing of depth of basecourse/subgrade interface and angle of internal friction in the basecourse,and the growth is slow as the value h/r（the ratio of surface course thickness to load equivalent radius）is greater than 2.5.The upper shakedown load decreases with the increasing ratio of E/E0,and the upper shakedown load is the maximum when E/E0 s 1.0.The upper shakedown load is greater than elastic limit and lower shakedown load,lesser than plastic limit.Our researches show that the shakedown limit based on the upper bound theorem can accurately represent the bearing capacity of pavement structures and could be a new reference to the analysis and design of pavement.