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Annual Report 2016
SAMCoT
COASTAL TECHNOLOGY
Coastal zone development in the Arctic is quite demanding. The construction of roads,
harbours and other facilities in the Arctic faces several challenges, e.g. exposure to
the combined action of waves, currents and ice, high coastal erosion rates, building on
permafrost soils, remoteness and the lack of local material suitable for construction
purposes. Moreover, climate changes may result in a warmer Arctic with less sea-ice cover
leading to higher wave forces on structures, more unstable permafrost soils and increasing
rates of coastal erosion during the service lifetime of our structures. Different research
projects address these general challenges in response to SAMCoT’s industry partners’ needs
for innovation.
The goal of WP6 is to develop new knowledge, and analytical and numerical models needed
by the industry to improve the prediction of Arctic coastal erosion and the influence of
climate changes. This is essential for the design of environmentally friendly and sustainable
coastal structures and technologies.
THERMO-HYDRO-MECHANICAL (THM) CONSTITUTIVE MODELS
In 2016 postdoc Seyed Ali Amiri and PhD candidate Me-
hdi Kadivar worked to develop Thermo-Hydro-Mechani-
cal (THM) constitutive models to simulate the behaviour
of frozen soils. They have developed an elastic-plastic
constitutive model for simulating the mechanical
behaviour of saturated frozen soils and have published
the theoretical foundation of the model in the Canadian
Geotechnical Journal. The model was later implemented
in PLAXIS and the beta version of the model, together
with a user manual, was released by PLAXIS towards the
end of 2016. In November 2016, Amiri and others from
NTNU visited the PLAXIS office in Delft and conducted
an introductory workshop about the model.
Considering the time-dependent behaviour of frozen
soil, Amiri upgraded the elastic-plastic model to an
elastic-viscoplastic version. The new model is also
implemented in PLAXIS and can be used by other
researchers upon request. The theoretical basis of
the elastic-viscoplastic model has been published
in the European Journal of Environmental and Civil
Engineering.
The simulation considers a chilled pipeline buried in a cold
region. The cooled fluid in the pipeline has a temperature of
-20
⁰
C, and the air temperature has dropped from +20
⁰
C to
-5
⁰
C. This decreases the ground temperature and freezing
will start. Freezing may result in frost heave which is defined
as the ground expansion caused by water migration that
supplied growing ice lenses. Predicting the frost penetration
and frost heave is important in the design and safety of
structures in, or on, frost-susceptible soils. The figure shows
the simulation results for the ground deformation and frost
penetration (white line) after 210 days.