This paper presents the results of shaking table model tests and numerical modelling studies which were carried out to gain insight to liquefaction mechanisms in layered sand deposits. The experiments were performed by means of a shaking table testing system on uniform sand columns, silt interlayered sand columns and two layered sand columns deposited at various relative densities and subjected to different input excitations. Excess pore water pressures generated during dynamic loading were measured by pore water pressure transducers installed at three different depths. The physical model tests are also numerically modelled to analyse the dynamic behavior of uniform and layered sand columns by using the Towhata-Iai liquefaction model. The experimental and numerical analysis results revealed that the presence of a less permeable silt interlayer within the sand deposit and existence of a loose sand layer underlying dense sand deposits can have significant effect on the liquefaction behavior. © 2008 ASCE.