The advanced numerical analysis of liquefaction problems is discussed in this paper. The ability of such analysis to accurately simulate behaviour during earthquakes depends on the ability of the constitutive model to represent real soil behaviour. Key requirements for constitutive models targeting liquefaction problems are discussed, and the use of the state concept approach for modelling cyclic behaviour of soils is described. Seismic analysis of two case studies and physical model tests are used to illustrate the application of the seismic effective stress analysis and to demonstrate both its enormous potential and areas where further improvements are needed.