The shear strength and compression properties of stiff Boom clay from Belgium at a depth of about 16.5 to 28 m were investigated by means of cone penetration and laboratory testing. The latter consisted of index classification, constant rate of strain, triaxial, direct simple shear and unconfined compression tests. The Boom clay samples exhibited strong swelling tendencies. The suction pressure was measured via different procedures and was compared to the expected in situ stress. The undrained shear strength profile determined from cone penetration tests (CPTs) was not compatible with the triaxial and direct simple shear measurements, which gave significantly lower undrained shear strength values. Micro-computed tomography (μCT) scans of the samples showed the presence of pre-existing discontinuities which may cause inconsistencies in the comparison of the laboratory test results with in situ data. The experimental data gathered in this study provide useful information for analyzing the mechanical behaviour of Boom clay at shallow depths considering that most investigations in the literature have been carried out on deep Boom clay deposits.

The vibratory installation of monopiles as foundation for offshore wind turbines is considered a plausible solution next to the conventional installation method (impact-hammering). One of the main advantages is the lower noise emissions, reducing harm to the marine life. However, knowledge on the effects of the vibratory installation parameters on the lateral response of monopiles – and how these effects differ from those caused by impact-driving – is limited. This paper presents the results from an ongoing Joint Industry Project (SIMOX) with focus on 1g laboratory tests carried out in a 9.0m x 5.5m x 2.5m tank with saturated sand at Deltares, the Netherlands. The tests involve the installation (impact and vibratory) of scaled piles with 32 cm diameter, embedment length of 1.5 m and two wall thicknesses. The lateral loading regime consisted of monotonic and cyclic lateral loading. The results show the effect of soil density and different installation parameters of vibratory installation on the lateral response of the piles compared to a conventional impact installation.

The response of monopiles to lateral loading has attracted considerable research interest in recent years. As monopile foundations are exposed to ever-harsher environmental conditions, the engineering tools used for their simulation should continually update and improve. Recently, the challenge of simulating the behaviour of monopiles under lateral loads has been addressed to a significant extent through a combination of numerical modelling and experimental data. Although monotonic response calculations are still relevant to monopile design, it should be acknowledged that offshore environmental loads are inherently cyclic. To improve the engineering tools for the simulation of cyclic monopile behaviour and our understanding of the relevant geotechnical mechanisms, this study presents and discusses the outcome of advanced 1D cyclic soil reaction modelling of monopile-soil interactions employed to simulate centrifuge data conducted as part of the MIDAS research project. The memory-enhanced p-y model proves capable of simulating cyclic ratcheting behaviour in complex loading histories, which promotes the discussion for the evolution of relevant soil reaction mechanisms during cyclic loads. Finally, preliminary calibration strategies for the employed cyclic soil reaction models are presented.