Enhanced plasticity modelling of high-cyclic ratcheting and pore pressure accumulation in sands

Predicting accurately the response of sands to cyclic loads is as relevant as still challenging when many loading cycles are involved, for instance, in relation to offshore or railway geo-engineering applications. Despite the remarkable achievements in the field of soil constitutive modelling, most existing models do not yet capture...

Comparison of new memory surface hardening models for prediction of high cyclic loading (Comparaison de nouveaux modèles de surface de mémoire à durcissement pour la prévision de fortes charges cycliques)

This paper presents an objective comparison between two recent constitutive models employing the concept of the hardening memory surface to predict the high cyclic loading behaviour of granular soils. The hardening memory surface is applied to the well-known Severn-Trent sand and the SANINSAND04 constitutive models. While the addition of the new...

Capturing cyclic mobility and preloading effects in sand using a memory-surface hardening model

Earthquake-induced build-up of pore water pressure may be responsible for<br/>reduced soil capacity, while the accumulation of shear strains may lead to a violation of serviceability limits. Predicting accurately the soil cyclic behaviour in relation to seismic numerical simulations is still a challenging topic in many respects. Efforts are...

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...

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...

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...

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...

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,...

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...

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,...