Tasmania Chapter

Dynamic saturated soil and pore fluid interaction modelling using FEM and combined DEM-LBM

Professor Andrew Chan

Abstract

Earthquake induced liquefaction has caused extensively damage to various cities and one of the most notable one is the damage caused to Christchurch during the Lyttelton earthquake on 22nd February 2011. Liquefaction occurs because of the interaction between the soil particles and its pore fluid. The seminar will describe the cause of liquefaction and the typical damage it causes. Then the mathematical model, Biot formulation, governing the saturated soil and pore fluid interaction will be given together with the stress-strain relationship used in modelling the material behaviour. Computational results and their comparison with centrifuge experiments will then be presented to validate the approach. Besides earthquake induced liquefaction, wave-induced liquefaction at the seabed can also be analysed using the same formulation. This can have a major effect on the stability of offshore foundations. Results of some of the numerical examples obtained will also be presented.

Strictly speaking, soil cannot be described as a continuum especially when liquefaction or fluidisation phenomenon occurs and discrete element method provides a better description of the interaction between the soil particles. On the other hand, the Lattice Boltzmann method provides a simple but microscopic description of the fluid thus allowing a detailed modelling of the interaction between the particles and the pore fluid. Results obtained using this combined DEM-LBM strategy for soil erosion due to pipe leakage will be presented and its strengths and weaknesses in comparison with the finite element method will be discussed.

About Professor Andrew Chan

Andrew joined the University of Tasmania in March 2015 to take up the position of Professor and Head of School of Engineering and ICT. He completed his PhD at the University of Wales, Swansea. He has spent time working as a Postdoctoral Research Assistant at Cambridge University, and has lectured in the Department of Civil Engineering at the University of Glasgow and was Reader and Professor in Computational Engineering at University of Birmingham. He is currently also a Contract Professor and part-time PhD supervisor for Harbin Institute of Technology in China. Professor Chan has a wide research interest. He is one of the world leading experts in the use of the finite element method of static and dynamic fully coupled soil and pore-fluid interaction and the author of two comprehensive Finite Element packages for deformable porous media and pore fluid interaction.

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