Abstract: Slope topography can significantly amplify seismic effects, threatening the seismic safety of pile foundations on slopes. To elucidate the mechanism by which slope topography affects pile foundation vibration, an analytical method is proposed to solve the dynamic response of slope-pile under SH wave incidence. Firstly, based on the wave function expansion method, the free field displacement of slope soil under SH wave with arbitrary incident angle is solved. Then, the interaction between pile and vibrating soil is simulated by the beam on Pasternak foundation model, and the dynamic response of pile is solved by applying the boundary conditions of pile foundation. The calculation results are compared with the finite element simulation results, showing good agreement, which effectively verifies the method’s accuracy. The effects of pile-soil modulus ratio, pile slenderness ratio, slope gradient and SH wave frequency on the vibration of slope-pile system are examined through parameter analysis. The results show that the topographic effects significantly increase pile foundation vibration when the pile-soil modulus ratio (100) is low, the pile slenderness ratio (10) is low, at specific slope gradients (90°, 150°), and specific vibration frequencies. This study provides a scientific basis for further improving the seismic design theory of slope bridge piles in high-intensity mountainous areas in the west.

Key words: slope topography effect, pile-soil interaction, dynamic response, beam on Pasternak foundation model, SH wave