Response of rigid drainage pile–superstructure–quay wall system under lateral spreading

Many examples of earthquake damage show that liquefied lateral spreading is the main cause of pile foundation failure. Rigid drainage piles (RDPs), with two drainage grooves and plastic drainage plates, are a new type of liquefaction-resistant pile that can take into account the bearing capacity and drainage function. A series of 1g shaking table tests was carried out to analyse the seismic response of an RDP–superstructure–quay wall system subjected to lateral spreading. Three levels of earthquake intensities – small (peak ground acceleration (PGA) of 0.05g), moderate (PGA = 0.1g) and large (PGA = 0.2g) – were investigated. The improvement in the anti-liquefaction performance using RDPs was analysed. The influences of far-field (FF) and near-field (NF) ground motions were also examined. The experimental results showed that RDPs can effectively reduce the liquefaction degree and the horizontal flow of the sand stratum. In addition, the internal force and displacement of the superstructure built on RDPs were small. The seismic response due to NF ground motion was found to be more significant than that of the FF ground motion, but the effects of FF ground motion cannot be disregarded. The results of the tests could provide useful information for the design of RDP groups in a typical pile–superstructure–quay wall system.