Performance of gravel drains, installed as one of remedial measures against liquefaction, is studied by conducting large scale model tests. The tests are conducted with a container, set up on the shaking table, made of a stack of 64 aluminum rings; the rings of about two meters in diameter being stacked to the height of about two meters. The tests have been conducted under sinusoidal as well as earthquake input motions. The results of the tests are analysed by using a model of consolidation with an additional term for generating excess pore water pressures.
　The following conclusions are obtained: (1) the effect of the gravel drain is to reduce the rate of increase in pore water pressures and to increase the rate of
dissipation in pore water pressures; (2) the maximum excess pore water pressures can be reduced by the gravel drain but they are very sensitive to the slight variations in the properties of the sand deposit and the intensity level and other properties of the input motions; (3) the simple model used for the analyses provides a reasonable approximation on the performance of the gravel drain within the range of the safety factor of two.