Numerical Analysis of Liquefaction in a River Levee on Soft Cohesive Ground

Abstract

During the 2011 off the Pacific coast of Tohoku earthquake, liquefaction at the bottom of embankments extensively damaged river levees in the Tohoku and Kanto areas. This study presents preliminary numerical simulation of liquefaction in a river levee on soft cohesive ground along the Eai River during the earthquake. Static analysis reproduced the initial state of stress and moisture in such an embankment before the earthquake. Static analysis showed a decrease in mean effective stress and an increase in water content at the bottom of the embankment due to the settlement of soft cohesive ground. The effect of initial stress and moisture conditions on the seismic responses of the river levee are discussed through dynamic threephase coupled analysis with an initially deformed configuration and moisture distribution. Numerical results showed that stress relaxation in the embankment caused an increase in settlement at the crest of embankment.