Application of Three-dimensional Static Analysis to Evaluation of Residual Settlement and Inclination of Spread Foundation Induced by Liquefaction

Abstract

The 2011 off the Pacific coast of Tohoku Earthquake has caused significant liquefaction damage to residences that led us to recognize the importance of damage prediction and countermeasure evaluation for spread foundation structures. To estimate residual settlement and inclination of the structures properly, influence of shapes, neighboring positions and eccentric loading need to be considered; accordingly, numerical approach is suitable. We, then introduced the methodology of ALID, that has been widely used for two-dimensional analysis, to the three-dimensional analysis code. In this paper, we firstly explain the detail of the three-dimensional analytical method, then verified the applicability of the method through validation analyses on centrifuge model tests and post-analytical assessments on field investigation results obtained after the 2011 Earthquake in Urayasu-city. Finally, we conducted numerical experiments focusing on residual settlements and inclinations under four neighboring houses. By examining results of the numerical experiments from viewpoint of influence of neighboring positions and ground water levels, we provided expertise that may contribute to estimate residual settlement and inclination of relative low-rise structures in a future earthquake.