A centrifugal experimental investigation on the seismic response of group-pile foundation in a slope with an inclined weak intercalated layer

In this study, a dynamic centrifuge model was constructed to investigate the seismic performance and dynamic deformation of a group-pile foundation embedded in a slope with an inclined weak intercalated layer. The performance was investigated under El-Centro and artificial waves with different input peak ground accelerations (PGAs). The seismic performance of the foundation was indicated by the two piles' axial forces and bending moments as monitored by strain gauges, whereas the dynamic deformation was mainly focused on a mass block's movement and was measured by laser displacement meters. Conventionally, the peaks of both axial force and bending moment increased with an increase in the input PGA. However, the vertical distribution of the bending moment along the pile were in a nonlinearly increasing trend from the pile end to top, especially for the case of the input PGA >= 0.15 g, whereas the axial force's distribution was more uniform. In this case, the bending moment at the pile top played a dominant role for the whole pile. Moreover, the positive peaks of axial force and bending moment were mostly unequal to their absolute negative peaks, especially for the "Pile-II" under intensive excitations. In addition, the axial force and bending moment peaks of one of the two piles were generally no more than twice the peaks of the other one. Furthermore, the bending moment of the pile top had a strong relationship to its horizontal displacement and demonstrated the dynamic stiffness of the piles to some extent.