飞机荷载作用下非均匀道基动力响应分析

针对山区机场道基沿跑道方向挖填交替的特点，通过沿跑道横向Fourier变换，提出适用于飞机移动荷载作用下山区机场跑道动力响应分析的半解析有限单元法，导出相应的有限元列式，编制有限元分析程序，通过算例验证方法及程序的正确性。分析单轮荷载移动速度、机场道面结构形式以及挖填交替非均匀道基形式对道基土体动应力的影响。结果表明：道基土体动应力路径呈蛋形，各动应力分量的峰值小于单轮静压力的2%；随着荷载移动速度加快，土体动应力路径逆时针偏转，动应力峰值和影响深度明显增加；与刚性道面结构相比，柔性道面结构下土体动应力沿跑道纵向和横向衰减快，但动应力峰值和影响深度更大；挖填交替界面附近土体动应力集中，集中系数达约1.4。

Dynamic response analysis of inhomogeneous subgrade subjected to moving aircraft loads

 Considering the alternant excavating-filling along the runway direction of airport subgrade in mountainous area, a semi-analytical finite element method is proposed to analyze the dynamic responses of runway subjected to moving aircraft load，in which Fourier transform in the transverse direction of the runway is used. The corresponding finite element formulations are derived, and the finite element analysis program is coded. Examples of practical application validate the accuracy of the method and the program. The influence of the load speed, the pavement types, and the inhomogeneous subgrade on the dynamic responses of the subgrade is analyzed, respectively. The results show that the dynamic stress path of subgrade soil is egg shaped. The peak value of the dynamic stress components in subsoil is less than 2% of the static pressure under single-wheel load. With the increase of load speed, dynamic stress path rotates counterclockwise, the peak of dynamic stresses and the influential depth increase significantly. Compared with the rigid pavement, dynamic stresses in the subsoil under flexible pavement decay faster along the longitudinal and transverse directions, but stress peaks are bigger and influential depth is deeper. Near the excavating-filling interfaces, the dynamic stresses in soil concentrate with a factor up to 1.4.