Calibration of a hydromechanical discrete-continuum model and liquefaction analysis of a staurated soil system
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Authors
Rashique, Utsa
Issue Date
2024-12
Type
Electronic thesis
Thesis
Thesis
Language
en_US
Keywords
Civil engineering
Alternative Title
Abstract
This dissertation presents a calibration of a hydromechanical discrete-continuum model of granular media. The approach emphasizes the critical role of particle-scale characteristics, such as size, shape, and surface texture, in influencing the macroscopic behavior of a granular system. While challenges exist in quantifying these micro-level properties, basing model calibration on such parameters demonstrably yields realistic system responses across diverse loading conditions. This approach facilitates the development of complex and robust numerical models that are easy-to-calibrate. The research highlights the significant influence of shape parameters, like sphericity and roundness, on the shear behavior of granular materials. Traditional contact models, like the Hertz-Mindlin model, can sometimes fall short due to their assumption of perfectly spherical contact surfaces. This limitation is addressed through the implementation of of general models like the J\"{a}ger model, which account for local variations in particle angularity. This allows for a more accurate representation of a wider range of particle conditions. Once calibrated, the model is then employed in constant volume simple shear tests, demonstrating an ability to reproduce liquefaction curves that closely match experimental data. This performance surpasses the accuracy achieved with models employing spherical particles and conventional contact models. Furthermore, the calibrated model is utilized to simulate a sheet pile supporting a dry soil backfill under dynamic loading. The resulting simulations produce realistic outcomes, that accurately capture the results obtained experimentally in centrifuge tests, including lateral displacement and settlement of the backfill soil and rotation of the retaining wall. Finally, this dissertation presents an integration of the discrete model of the particles with an average Navier Stokes model of the pore fluid, resulting in a coupled CFD-DEM model for a saturated soil-sheet pile system. This coupled framework exhibits reasonable accuracy, effectively replicating both the sheet pile response and the dynamics of pore pressure within the soil. Notably, the model maintains consistency across crucial parameters, including coordination number, acceleration, and the stress-strain response. The findings from this model aligns well with established theoretical predictions and existing experimental data.
Description
December 2024
School of Engineering
School of Engineering
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY