Centrifuge modeling of dynamic behavior of pile-reinforced slopes during earthquakes

A series of centrifuge model tests of sandy slopes were conducted to study the dynamic behavior of pile-reinforced slopes subjected to various motions. Time histories of accelerations, bending moments and pile earth pressures were obtained during excitation of the adjusted El Centro earthquake and a cyclic motion. Under a realistic earthquake, the overall response of the pile-reinforced slope is lower than that of the non-reinforced slope. The histories of bending moments and dynamic earth pressures reach their maximums soon after shaking started and then remain roughly stable until the end of shaking. Maximum moments occur at the height of 3.5 m, which is the deeper section of the pile, indicating the interface between the active loading and passive resistance regions. The dynamic earth pressures above the slope base steadily increase with the increase of height of pile. For the model under cyclic input motion, response amplitudes at different locations in the slope are almost the same, indicating no significant response amplification. Both the bending moment and earth pressure increase gradually over a long period.