ABSTRACT
Multiple occurrence of sand liquefaction has been reported in the past case histories worldwide, including those on the 2010-2011 Christchurch Earthquakes in New Zealand and the 2011 Off the Pacific Coast of Tohoku Earthquake in Japan. In order to reveal the multiple-liquefaction behavior, a series of 1-g shaking table tests on level ground and another series of cyclic stacked-ring shear tests on hollow cylindrical specimen with/without initial static shear are conducted. It is observed that, though overall densification is observed in the two types of tests, the re-liquefaction resistance could either increase or decrease by the liquefaction history. The response during the current liquefaction stage is more predominantly affected by the immediate-past liquefaction history than by the current relative density that is averaged over the full depth. In case of the cyclic stacked-ring shear tests with initial static shear, significant effects of anisotropy that has been induced by the liquefaction history are also observed.
