SAMCoT - Annual Report 2015

SAMC

• ANNUAL REPORT 2015

in this direction and reasonable results are already being

achieved.

Since August 2015, Kadivar has been a visiting researcher

at the laboratories of the NGI working with NGI’s frost

heave cell device to understand the behaviour of soil during

freezing and to measure the amount of frost heave. By

using NGI’s device, it is possible to monitor the temporal

freezing behaviour of soil at different temperatures. The

soil sample, either intact or reconstructed, is placed into

the cell and adjustable temperature is applied from the top,

bottom and side of the sample. The freezing characteristics

of soil that can be studied by this device are the location

of freezing front, expansion of soil sample and amount of

water intake from an external source during the test. The

location of the freezing front is obtained by checking the

temperature at the sides of the sample in different time

steps. The main purpose of Kadivar’s work at NGI is to

study the frost susceptibility of normally-consolidated clay

at different temperatures. Mehdi will sum up his work at

NGI and come back to NTNU by the end of January 2016.

CFD model REEF3D

PhD candidate Nadeem Ahmad is working on the three-

dimensional numerical modeling of local scour in cold

climates. Ahmad

‘

s position, although strongly linked to

SAMCoT is funded through the affi liated Norwegian-

Polish research project “Vulnerability of the Arctic coasts

to climate changes” (ARCOAST). He uses the open-source

computational fluid dynamics (CFD) model REEF3D, devel-

oped by the CFD group at the Department of Civil and

Transport Engineering at NTNU, Trondheim. REEF3D has

a wide range of applicability within the fi eld of coastal

and ocean engineering, simulating wave hydrodynamics,

Coastal zone development in the Arctic is quite demand-

ing. The construction of roads, harbours and other facili-

ties in the Arctic faces several challenges, e.g. exposure

to combined actions from waves, currents and ice, high

coastal erosion rates, building on permafrost soils and

the remoteness and lack of local material suitable for

construction purposes. Moreover, climate change may

result in a warmer Arctic with less sea-ice cover leading to

higher wave forces on structures, more unstable perma-

frost soils and increasing rates of coastal erosion during

the service lifetime of structures.

In order to address these general challenges according

to the industry partners’ needs for innovation, several

research projects have been carried out.

Simulating the behaviour of frozen soils

Postdoc Seyed Ali G. Amiri and PhD student Mehdi Kadivar

areworking to developTHMconstitutivemodels for simulat-

ing the behaviour of frozen soils. Amiri has developed an

elastoplastic model to describe the mechanical behav-

iour as well as the behaviour due to variation of tempera-

ture. The proposed model is able to represent many of the

fundamental features of the behaviour of frozen soils such

as ice segregation phenomena and strength-weakening

due to pressure melting. Currently, this model is being

implemented in the commercial software package PLAXIS

and will soon be ready to use in geotechnical engineering

practice.

Amiri submitted a paper describing his model to the

Canadian Geotechnical Journal. The reviewers suggested

minor revisions and we expect this paper to be published

quite soon in 2016. Amiri’s second step is to extend his

model to consider the effect of strain rate on the stress-

strain behaviour of the soil. Good progress has been made

Figure WP6_2 Norwegian Geotechnical Institute`s (NGI) frost

heave cell device.

Figure WP6_1 Three-dimensional view of the yield surfaces in

p*- q*- S space