INFLUENCE OF EXCITATION DIRECTION ON FLOATATION OF BURIED PIPES DURING LIQUEFACTION

Abstract

 Previous studies using model tests and analyses have revealed that the floatation of buried pipe was triggered by the buoyancy caused by liquefaction and floatation amount is caused by that the ground around the pipe moves to the bottom of the pipe. Despite advances in numerical analysis technology, there are limited methods to accurately evaluate the soil particles’ moving phenomenon. In addition, most of the existing model tests were conducted with horizontal excitation to the cross section of structure. In this study, horizontal excitation tests were conducted in both the pipe cross section and the pipe axis plane under the same underground conditions, in order to evaluate the effect of excitation direction on the floatation amount of buried pipes. When the pipe was not affected by near-surface sloshing, the floatation amount was 0.5 to 0.87 times smaller when the pipe was excited in the axial direction than when it was excited in the direction of cross section.