Shaking table test on free field considering soil liquefaction

Shaking table model tests on the free field considering the soil liquefaction are described in this paper.A flexible container is fabricated to minimize the box effect.Saturated sand soil is employed as model soil.In the tests,macro-phenomena of soil liquefaction due to natural earthquake are reproduced well,such as sand boiling,water spouting and soil surface sinking.Some important findings from the present tests are as follows.The natural frequency of soil decreases and the damping ratio of soil increases with the increase of the shaking.The liquefied soil can filter the vibration. The response of the acceleration amplitude is in K shape along the height.The phenomena of the transient minus pore pressure occurred in the test.Pore water pressure does not always dissipate in short time immediately after the excitations,but it may keep on increasing too.