This report presents the results of a three-year theoretical and experimental investigation of the response of multiphase porous media to strong dynamic loadings. A material element model was developed to automate the determination of parameter values for multiphase material models and to predict the response of saturated porous materials to arbitrary stress, strain and fluid flow boundary conditions. Laboratory tests to measure fluid flow through porous media were conducted over a wide range of pressure gradients in granular materials and porous rock. The results of those tests were used to develop a unified fluid friction model. A laboratory apparatus was constructed for the purpose of studying wave propagation through saturated porous media. A suite of dynamic tests was performed on a porous stainless steel specimen, and the results of those tests were compared with detailed multiphase numerical simulations. The simulations were in excellent agreement with the laboratory measurements. With guidance from simulations, it was possible to identify in the test data, the wave of the second kind. This disturbance, which propagates at a speed significantly lower than the compressional wave, appears to be associated with a surge of pore fluid within the porous skeleton, and has previously only been predicted by analysis. Wave propagation, Two-phase modeling, Permeability Soil and rock properties, Liquefaction, Geotechnical analysis, Numerical analysis(Geotechnical).