Two dimensional hydrological simulation in swelling/shrinking
peat soils
M. Camporese, P. Salandin
Dept. Hydraulic, Maritime, Environmental, and Geotechnical Engineering,
University of Padova, Padova, Italy
C. Paniconi
Centre Eau, Terre et Environnement, Universite' du Que'bec, Canada
M. Putti, P. Teatini,
Dept. Mathematical Methods and Models for Scientific
Applications, University of Padova, Padova, Italy
ABSTRACT
Peat soils respond to drying/wetting cycles due to evapotranspiration and
precipitation with reversible deformations induced by variations of water
content. This process results in short-term vertical displacements of the soil
surface and induces variations in the peat hydraulic properties that cannot be
neglected when dealing with water flow problems in peatlands. A constitutive
model describing swelling/shrinkage dynamics in peat soils under unsaturated
conditions is implemented in a finite element simulator of Richards' equation.
The model entails a significant modification of the general storage capacity
term. The contribution of the saturated zone to the total deformation is taken
into account, using the theory of primary consolidation in the hypotheses of
completely reversible volume changes and constant compressibility. Simulations
have been carried out for a drained cropped peatland south of the Venice Lagoon
(Italy), for which a large data set of hydrological and displacement
measurements has been collected since the end of 2001. The considered domain
is a field section bounded by ditches, subject to rainfall, evapotranspiration,
and lateral drainage. The comparison between simulated and measured quantities
demonstrates the capability of the model to accurately reproduce both the
hydrological and deformation dynamics of peat.
