Simplified Analyses of Dynamic Pile Response Subjected to Soil Liquefaction and Lateral Spread Effects

Abstract

Pore water pressures greater than effective soil stress and subsequent liquefaction are known to occur in saturated sand deposits subjected to earthquake excitations. Liquefaction of soils can result in a reduction of soil strength and yields large settlement via lateral spreading. For superstructures supported on pile foundations embedded in such soils, these effects can be devastating. For example, the 1964 Niigata earthquake in Japan damaged the foundation piles under one of the piers of the 12 spans, 207 meter long Showa Bridge. After the earthquake, an excavation survey of damaged piles indicated that bending failure occurred due to the lateral spreading of river bed soils (Hamada, 1992). Similarly, in the 1994, when Northridge earthquake occurs, river bank areas between Santa Clarita and Fillmore, Highway 23 crosses over the Santa Clara River, where sand boils were observed near a bridge pier. Cracks induced by lateral spreading were found approximately 4.5 m away from the pier (Stephen et al., 2002). Afterward, in the 1995 Kobe Earthquake, quay walls along the coastline of Kobe moved up to several meters toward the sea as a result of lateral spreading (Tokimatsu and Asaka, 1998). Some papers also discuss liquefaction-induced lateral spread under the foundations of long-span bridges subjected to spatially-varying ground motions. (Abbas and Manohar 2002; Zerva and Zervas, 2002; Wang et al., 2004; Zerva 2009). More recent devastating earthquakes such as the March 2011 Tohoku earthquake in Japan and the January 2010 Haiti earthquake can be found and reported by EERI (Earthquake Engineering Research Institute) and USGS (United States Geological Survey).