Abstract: Pile foundation failures in lateral spreading ground have attracted the attentions of engineers and researchers since the Niigata and Alaska earthquakes. Study of typical cases of pile failures in lateral spreading ground and analysis of some previously proposed causes of the failures indicate that a mechanism which could completely explain the failures is yet to be found. By analyzing the failure of Showa Bridge during the Niigata earthquake through p-y method, this paper looks into influence factors for the failure of piles due to lateral spreading. Results show that appropriate p-y models for liquefied soil are vital in the analysis of piles in lateral spreading ground; further understanding and better aseismic design of piles in lateral spreading ground depends on the development of effective p-y curve models for liquefied soi

Key words: liquefaction, lateral spreading, pile foundation, p-y curve