WP3 – Laboratory testing and interpretation methods

Work Package 3 focuses on developing an efficient methodology for laboratory testing of shallow weak rock formations encountered at offshore wind sites. These materials are particularly challenging to characterise due to their complex structure and related behaviour requiring advanced laboratory test programmes. WP3 therefore aims to improve how weak rock is sampled, handled, tested and interpreted for offshore engineering applications.

The work package combines conventional and advanced laboratory approaches. Technologies such as the Multi-Sensor Core Logger (MSCL) can support rapid preliminary characterisation of the rock material, including the identification of discontinuities and weathering. In addition, advanced imaging methods such as X-ray computed tomography can help reveal how the material changes during testing and provide insight into the failure mechanisms that develop. (Figure 1).

Sample preparation is a particularly important topic in weak rock testing, especially for materials such as chalk. Disturbance during sampling and preparation can strongly influence the measured behaviour. WP3 therefore develops practical recommendations for sample handling and preparation in order to improve the reliability and repeatability of laboratory results.

A key objective is to establish guidance and recommendations for both static and cyclic laboratory testing programmes specific for weak rocks. These programmes are designed to capture the hydro-mechanical   behaviour of the material under representative offshore environmental loading conditions. The experimental testing will complement the rock characterisation by integrating laboratory results with in-situ data from WP 2, enabling a detailed multi-scale description of weak rocks. 

WP3 employs systems with high-capacity load cells with specialised testing systems capable of high-precision measurements under large deformations in both static and cyclic loading. This enables reliable testing across a wide range of strength and stiffness conditions, supports the derivation of cyclic strength contours, and provides data for calibrating advanced constitutive models following the scope of WP4.