Liquefaction phenomena are encountered in many engineering applications, especially, in geomechanics and earthquake engineering. Drawing our attention to fluid-saturated granular materials with heterogeneous microstructures, the modelling is carried out within a continuum-mechanical framework by exploiting the macroscopic Theory of Porous Media (TPM) together with thermodynamically consistent constitutive equations. In this regard, the solid skeleton of the water-saturated soil is described as an elasto-plastic material with isotropic hardening and a stress-dependent failure surface. The underlying equations are discretised and implemented into the coupled porous-media finite-element solver PANDAS and linked to the commercial finite-element package Abaqus via a general interface. This coupling allows the definition of complex intial-boundary-value problems through Abaqus, thereby using the sophisticated material models of PANDAS. To reveal the capabilities of this approach, two types of simulations have been carried out. At first, in order to get a detailed understanding of the porous-media soil model under transient loading conditions, a cyclic torsion benchmark is computed. In a second step, specific liquefaction phenomena are addressed, where the underlying initial-boundary-value problems are inspired by practically relevant scenarios.