ABSTRACT

It has been pointed out that the effect of partially saturated surface layer cannot be ignored when ground is liquefied. In this research, a series of centrifuge tests was made to clarify the effect of pore water inflow into a partially saturated surface layer during liquefaction. Four tests were carried out by changing groundwater level and pore fluid type (water or viscous fluid). The extent of the expansion of saturated area during and after shaking was different among the cases. Comparison between liquefied and non-liquefied cases indicated that there were obvious differences: a part of the unsaturated layer changed into a saturated one due to the seepage. In addition to the tests, three phase numerical analyses which take the effect of pore air pressure into consideration were performed for the centrifuge tests. The simulation well captured the change of the degree of saturation and the response of excess pore water.