1. Key Laboratory of Soft Soils and Geoenvironmental Engineering of the Ministry of Education, Zhejiang University, Hangzhou 310058, China;
2. Institute of Geotechnical Engineering, Zhejiang University, Hangzhou 310058, China
Abstract： 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.
