Numerical simulations of Holocene salt-marsh dynamics under the
hypothesis of large soil deformations
C. Zoccarato, P. Teatini
Dept. of Civile, Environmental and Architectural Engineering,
University of Padova, Padova, Italy
ABSTRACT
Salt marshes are vulnerable environments hosting complex interactions between physical and biological processes.
The prediction of the elevation dynamics of a salt-marsh platform is crucial to forecast its future behavior
under potential changing scenarios. An original finite-element (FE) numerical model accounting for the longterm
marsh accretion and compaction linked to relative sea level rise is proposed. The accretion term considers
the material sedimentation over the marsh surface, whereas the compaction reflects the progressive consolidation
of the porous medium under the increasing load of the overlying younger deposits. The modeling
approach is based on a 2D groundwater flow simulator coupled to a 1D vertical geomechanical module, where
the soil properties may vary with the effective intergranular stress. The model takes also into account the
geometric non-linearity arising from the consideration of large solid grain movements by using a Lagrangian
approach with an adaptive FE mesh. The numerical experiments show the potentiality of the proposed 2D model,
which consistently integrates in modeling framework the behavior of spatially distributed model parameters.
High sedimentation rates and low permeabilities largely impact on the mechanism of soil compaction following
the overpressure dissipation.
