Experimental investigation of drainage during earthquake-induced liquefaction

Abstract

Earthquake-induced liquefaction is typically viewed as an undrained phenomenon with undrained element tests forming the core of knowledge built around it. However, there is evidence to suggest that partial drainage could be taking place during an earthquake. In this paper two dynamic centrifuge tests are presented, in which drainage was restricted for a part of the soil by enclosing it within a chamber, in order to assess its importance. The hypothesis of undrained behaviour was found to be inappropriate for liquefied sand, even within the timescale of an earthquake. Fluid flow during the seismic motion was inevitable. Its effect on pore pressures and shear stress–shear strain response was controlled by the proximity of the boundaries.