According to effective stress dynamic analysis method and based on Byrne’s effective stress elastoplastic model

a new modified model is presented. This new model can consider these aspects such as rotation of principal stress axes

a little of gas

strain softening and stress redistributing after liquefaction. The analytical modules are programmed and interfaced with the FLAC code; then numerical simulating analysis of saturated sandy soil under single-point

two-point and multi-point explosion seismic waves respectively are carried out by using FLAC code which is a two-dimensional explicit program. The 3 kinds of fields such as the level

little-obliquity and slope grounds are considered; and the difference of the characteristic of saturated sandy soil between under explosion seismic waves loadings and natural seismic waves loadings are contrastively investigated. The results of numerical simulating indicate that the explosion liquefaction characteristics of saturated sandy soil can be well described with this model; the dynamic characteristics and liquefaction behavior of saturated sandy soil are different under different fields and different dynamic loadings.