Work Package 2 : Behaviour of Carbonate Soils

During the past decades, most of monopile and jacket piles for offshore wind turbine have been installed in siliceous sand or clay. The case of carbonated soil is not specifically treated in standards.  Carbonated rocks (including chalk) are however often encountered on the French coast. For these materials, the intention of the project will be to look at the behavior of a grout/rock interface under repeated cycles or ageing.

In order to improve the knowledge of soil-structure interaction on carbonate soil, direct 3D share test will be performed at the 3SR laboratory with the BCR3D. Some tests have been performed during the SOLCYP+ project but there is a need to enlarge the database and to look at a higher number of cycles. To carry out the experimental campaign, calcarenite blocks extracted from a French quarry will be used in order to work on relatively homogenous material.

The study will concentrate on the effect of type of loading (one way or two ways) encountered for drilled and grouted monopile or jacket piles.

In order to perform the 3D share tests, rock samples will be seal using cement and tested 28 days after. The first group of shear tests will allow characterizing the behavior at the rock/grout interface. Another group of tests is performed in order to perform a parametric study of the interface behavior.

Constant Normal Stiffness (CNS) tests will be conducted to include the effect of the rock compressibility in the observation of the cyclic degradation. Tests will be performed in both dry and saturated conditions to see the impact of the interstitial fluid.

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