Caisson foundation response during liquefaction induced lateral spreading.

Abstract

Caisson foundations are widely used as the foundation system of bridges, transmission towers, and scour vulnerable structures for transmitting high structural load to the soil beneath. In seismically active regions having potentially liquefiable soils, one important consideration is the effect of liquefaction induced lateral spreading on deep foundations. During this phenomenon, caissons are subjected to seismic forces and simultaneously it loses the lateral support of surrounding soil due to liquefaction and an extra kinematic loading acts because of the flow of the liquefied soil. In this present study, a caisson embedded in liquefiable soil in gentle sloppy ground has been modeled in finite element-based software package PLAXIS 3D for capturing the response of the caisson in laterally spreading ground. The proposed numerical model has been found to compare well with the available centrifuge test results. Further parametric study has also been performed for lateral response of the caissons in liquefying soil for different ground slopes, embedment depth to caisson width ratio, frequency and amplitude of the dynamic motion. Behavior of the rigid caisson foundations subjected to liquefaction induced kinematic loading have been thoroughly discussed in the present study to assist the seismic design of caissons embedded in potentially liquefiable soil.