© 2022 by ASME.Seabed liquefaction is the phenomenon by which the seabed soil loses its strength and stiffness, due to applied stress, and behaves like a non-Newtonian fluid. Seabed liquefaction can lead to severe failure of marine structures, such as buried pipelines or coastal breakwaters. Numerical modelling of liquefaction can provide valuable insights into the prevailing wave-structuresoil interaction. However, the holistic modelling of seabed liquefaction, including the transition from solid to liquid and back to solid soil, is challenging, due to the prevailing hydrogeotechnical processes. As a step towards the development of such a holistic numerical model of seabed liquefaction, this paper considers the modelling of the soil under a rocking plate as an idealised representation of a caisson breakwater as presented in . The numerical model has recently been presented in  and includes equations for the accumulation of pore pressure and a criterion to distinguish between the liquefied and non-liquefied regions. The numerical results are compared to the experimen-tal results taken from . Different numerical model setups are presented to overcome modelling challenges due to occurring punching shear failure.