Calcarenite used as foundation material for windmills

In order to increase the energy production from renewable sources, windmills are built in windfarms in the North Sea, where the winds are strong. Several challenges arise during the design of these offshore structures, and one of these is the foundations problem. Indeed, the base of a windmill is usually made by one or several piles driven into the seabed. The characterisation of the material constituting the seabed is therefore important. Calcarenite is a type of rock that can be observed in maritime environment. It can thus serve as a foundation material for a windmill. Several samples of calcarenite have been studied in the framework of this thesis in order to characterise this material. The first step was to select an appropriate model to describe the general mechanical behaviour of the rock as well as its failure behaviour. From this, a numerical finite elements model of the sample could be built. The next step consisted of several experiments designed to determine the physical characteristics of the rock. Then, more experiments were done to obtain the relevant parameters of the mechanical and failure behaviour of calcarenite. Finally, the finite element model could be correlated with the experimental observations