METHODS FOR EVALUATING RESIDUAL POST-LIQUEFACTION GROUND SETTLEMENT AND HORIZONTAL DISPLACEMENT

Abstract

ABSTRACT During the 1995 Hyogoken-Nambu earthquake, large vertical residual ground settlements and horizontal displacements extensively occurred in liquefied soils behind caisson-type quay walls where lateral movements of the walls towards sea were led by strong seismic shaking. Case studies further show that both significant vertical residual ground settlements and horizontal displacements were also induced by this earthquake in liquefied level sandy ground with a sufficiently large lateral extent where no significant initial shear stresses were present. The mechanism regarding the occurrence of the above phenomena is revealed through new post-liquefaction stress-strain constitutive analysis. Consequently, the residual post-liquefaction ground settlement and horizontal displacement are found to be interdependent of each other, so that neither cannot be determined separately in principle. A new methodology with pragmatic charts is developed for concurrently evaluating the residual post-liquefaction ground settlement and horizontal displacement in liquefiable ground. The prediction results using the proposed method agree with actual observations during the 1995 Hyogoken-Nambu earthquake.