We are seeking a full time PhD researcher with interests in granular physics, geomechanics, computer modelling and the discrete element methods (DEM) to join University of Twente (Netherlands) and work on micro- and meso-scale modelling to understand the initiation and dynamics of submarine landslides.
This project is part of the EU funded Marie Curie Doctoral Network POSEIDON – Improve offshore infrastructure resilience against geohazards towards a changing climate (www.poseidon-dn.eu). The overarching objective of POSEIDON
is to develop solutions to improve the resilience of offshore infrastructures. POSEIDON will train 13 researchers within a collaborative multidisciplinary and inter-sectorial network involving 9 universities, 3 research institutes and 4 industrial partners across Europe. Background and aim:
Hydromechanical phenomena at the pore scale, such as the development of elevated water pressure, and how they are coupled to the soil’s mesostructure, are key to the initiation and runout of submarine landslides. The fact that different regimes, e.g., quasi-static or fast-flowing, of the coupled particle-fluid systems interplay with the material’s particle- and meso-scale structures makes the prediction of submarine granular flows, from initiation to run-out, a scientific as well as a practical challenge.
Fully-resolved simulations of particle-fluid systems can be used to study the macroscopic behaviour of saturated granular materials. The effects of particle shapes and the mesostructure on the hydrodynamic coupling to the pore fluid can all be investigated with the coupled Lattice Boltzmann-Discrete Element Method.
We aim to develop a hydro-micromechanical
model of realistic granular soils using fully-resolved direct numerical simulation techniques, focusing on representative volume elements (RVEs). The goal is to understand the role of grain morphology and mesostructure in the avalanching and resting processes during submarine landslides, at various overpressure conditions. Objectives:
i) Apply an existing LBM-DEM numerical model to simulate the collapse of dense/loose granular masses over an inclined plane subjected to sudden increase of pore pressure;
ii) Incorporate realistic particle shapes in the LBM-DEM model and study the effect of grain morphology hydromechanical behaviour at NGI;
iii) Compare and validate the simulations at point i) and ii) with the pilot-scale laboratory experiments on granular–liquid mixtures at the Free University of Bolzano;
iv) Coarse grain particle scale information into continuum fields and understand the mass/momentum transfer and energy dissipation mechanisms that contribute to the triggering and runout of saturated granular flows. Expected Results:
i) A novel hydro-micromechanical numerical tool for modelling saturated granular masses in submarine landslides;
ii) A deep understanding of the interplay between structural properties (e.g., morphology and mesostructure) and pore water pressure on the saturated granular flows. Planned Secondment(s):
Dr. Nallathamby Sivasithamparam (NGI, 6 months): integrate particle shape within LBM-DEM.
Dr. Michele Larcher (Free University of Bolzano, 3 months): perform experiments in the inclined channel experimental device on dense/loose granular slopes and compare with simulations.