不同轮压分布形式对半刚性路面结构力学响应的有限元分析

Study of the mechanical response of semi-rigid pavement structure under different tire pressure distributions

针对轮胎接地形状的不规则性和轮压分布的不均匀性,运用三维有限元方法分析了轮压在圆形均匀分布、矩形均匀分布和矩形非均匀分布3种轮载作用形式下半刚性路面结构的力学响应.计算表明,轮压作用于路面的形状和非均匀性均对沥青路面的力学响应有显著的影响,尤其是超载时,圆形均布假设和矩形均布假设均不能正确反应半刚性结构层内部的剪切指标,只有矩形非均布假设能够很好地反应.研究提出,欠载及标准轴载时,可以采用圆形均布假设进行路面结构力学响应的分析;超载时,鉴于剪切指标对轮压非均匀性分布的敏感性,建议采用矩形非均匀分布荷载形式进行路面结构力学响应的分析及模拟仿真.

In the light of the in＇egular tire contact shape and the non-uniformity of wheel pressure, the mechanical response of semi-rigid pavement structure was studied by using the three-dimensional finite element method with three types of load distribution as uniform circular load, uniform rectangular load and non-uniform rectangular load. The results showed that both tire contact shape and non-uniformity of wheel pressure had significant impacts on the mechanical response of semi-rigid pavement structure, particularly sensitive to the shear indexes underoverloading conditions. Uniform circular assumption and uniform rectangular assumption could not accurately reflect the shear indexes on the effect of overload, compared with a good response under the nonuniform rectangular assumption. Two suggestions where proposed to estimate the mechanical response of semi-rigid pavement structure. The conventional tmiform circular load assumption can be used to analyze the mechanical response of pavement structure under the standard axle load and the underload conditions. The non-uniform rectangular load assumption should be used to analyze the mechanical response under overload conditions, considering the sensitivity of shear indexes.