水平・上下両加振による構造物基礎周辺地盤の液状化

Abstract

This study deals with experiments on the liquefaction of soft surface layers and the settle-ments of a rigid structural foundation and the surface layers caused by the liquefaction, underhorizontal and vertical shakings. Two directional motion has been achieved by making use ofa shaking table and a small vibration generator.It is shown that under two directional shaking the liquefaction and the settlement of thestructural foundation are not always caused in proportion to the excess pore water pressure, notwithstanding the excess pore water pressure under two directional shaking is greater thanthat under horizontal shaking. However, in some cases there are test data which mean thesettlement under two directional shaking is greater than that under horizontal shaking.On the basis of these results, the phase lag and the excitation frequency ratio are alsodiscussed between the horizontal and the vertical motions of two directional shaking.