In this work a fully coupled model for the dynamic analysis of partially saturated plastic soils including water and airflow is presented. The innovative contribution of this research mainly consists in the extension of the model to the dynamic analysis of porous media with two simultaneously flowing immiscible fluids. The model adopts the solid displacements and the pressures of fluids as primary unknowns from which all the other local quantities are derived. The governing equations are presented in form of partial differential equations, then the algebraic form is derived by finite element discretisation in space and using the Newmark method for the time integration. The model has been validated with respect to documented experiments on partially saturated soil in quasi-static condition. Moreover applications of the numerical model in dynamic conditions have been developed and the results are commented and compared with experiments of various researchers where available.