移动荷载下各向异性层状地基-柔性路面结构动力响应的半解析解

SEMI-ANALYTICAL SOLUTION FOR DYNAMIC RESPONSE OF ANISOTROPIC LAYERED FOUNDATION-FLEXIBLE PAVEMENT STRUCTURE UNDER MOVING LOADS

  • 摘要: 提出了移动荷载作用下各向异性层状地基上柔性路面结构动力响应分析的半解析解法。基于土-结构相互作用理论,建立了柔性路面-层状地基的动力耦合模型。对近场道路结构建立波数域有限元模型,基于精细积分及谱元法原理建立远场地基的谱元模型,利用子结构法来确定近-远场耦合界面处的边界条件,进而实现近场和远场结构的耦合,利用快速Fourier变换获得柔性路面在时空域的动力响应解答。该文方法既可以考虑道路结构的几何特性,也可以计入地基层状分布及各向异性特性的影响。近场有限域模型尺寸不会受到地基层数及层厚的影响,数值求解稳定。通过与解析解的对比,验证了提出方法的有效性与合理性。数值算例对比分析了道路-地基耦合模型与以往整体层状道路模型所得动力响应的差异,并讨论了道路结构层弹性模量的影响规律。

     

    Abstract: A semi-analytical solution for the dynamic response of a flexible pavement structure on an anisotropic layered foundation under a moving load is proposed. Based on the theory of soil-structure interaction, a road-foundation coupling model for the flexible pavement and layered foundation is established. A wavenumber finite element model is established for the near-field road structure. Based on the precise integration and spectral element method, a novel spectral element model is established for the far-field foundation. According to the substructure method, the boundary conditions at near-far field coupling interface are determined, and the near-field and far-field structures are coupled together. Using fast Fourier transform, the dynamic response of the flexible pavement in the time and space domain can be obtained. The proposed method can consider the geometric characteristics of the road structure and take the stratification and anisotropy of foundation into account. The dimension of the near-field wavenumber finite element model is not affected by the number and thickness of foundation layers, and the computational result is stable. Both the validity and rationality of the proposed method are verified by comparing with the analytical solutions. Numerical examples are presented to reflect the difference between the dynamic responses obtained by using the road-foundation coupling model and previous overall layered model, and the effect of elastic modulus of road layer is also discussed.

     

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