Large diameter laterally loaded piles in sand: Numerical evaluation of soil stress paths and relevance of laboratory soil element testing

This paper uses 3D numerical analyses to investigate the stress path experienced by soil elements around large diameter piles in sand subjected to monotonic drained lateral loading. Inspection of the loading-induced stresses in the soil revealed the multiaxial nature of these stress paths, which are characterised by rotation of one or more...

Influence of static–cyclic load misalignment on the drained tilting response of offshore monopiles in sand

Offshore monopile foundations are exposed to misaligned wind and wave loadings, which are respectively dominated by (nearly) static and cyclic load components. While the response of these systems to unidirectional cyclic loading has been extensively investigated, only a few studies have been devoted to the realistic case of misaligned static...

Impact of cyclic strain accumulation on the tilting behaviour of monopiles in sand: An assessment of the Miner's rule based on SANISAND-MS 3D FE modelling

Offshore monopiles accumulate permanent tilt under long-lasting cyclic environmental loads. Accurate prediction of monopile tilt is key to assessing their serviceability, and requires a fundamental understanding of loading history effects. While both experimental and numerical studies are shedding light on this matter, this work uses step-by...

From cyclic sand ratcheting to tilt accumulation of offshore monopiles: 3D FE modelling using SANISAND-MS

Serviceability criteria for offshore monopiles include the estimation of long-term, permanent tilt under repeated operational loads. In the lack of well-established analysis methods, experimental and numerical research has been carried out in the last decade to support the fundamental understanding of monopile-soil interaction mechanisms, and...

3D FE-Informed Laboratory Soil Testing for the Design of Offshore Wind Turbine Monopiles

Based on advanced 3D finite element modelling, this paper analyses the stress paths experienced by soil elements in the vicinity of a monopile foundation for offshore wind turbines subjected to cyclic loading with the aim of informing soil laboratory testing in support of monopile foundation design. It is shown that the soil elements in front of...

Memory-Enhanced Plasticity Modeling of Sand Behavior under Undrained Cyclic Loading

This work presents a critical state plasticity model for predicting the response of sands to cyclic loading. The well-known bounding surface SANISAND framework by Dafalias and Manzari is enhanced with a memory surface to capture micromechanical, fabric-related processes directly affecting cyclic sand behavior. The resulting model, SANISAND-MS,...

Prediction of oedometer terminal densities through a memory-enhanced cyclic model for sand

Predicting the cyclic response of soils is still challenging in many geotechnical applications. In this area, the continual efforts on the constitutive modelling of cyclic sand behaviour demand new and reliable dataset for model validation - even more so for loading conditions involving numerous loading cycles ('high-cyclic' loading). This paper...

Modelling the cyclic ratcheting of sands through memory-enhanced bounding surface plasticity

The modelling and simulation of cyclic sand ratcheting is tackled by means of a plasticity model formulated within the well-known critical state, bounding surface SANISAND framework. For this purpose, a third locus – termed the ‘memory surface’ – is cast into the constitutive formulation, so as to phenomenologically capture micro-mechanical,...