Suction effect of skirted mud mat of GRP covers under wave loads
Master thesis
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https://hdl.handle.net/11250/3079648Utgivelsesdato
2023Metadata
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Sammendrag
To mitigate potential risks of soil and structural failures in offshore foundation systems, it is crucial to examine seabed soil behavior near the structure especially near the skirtfaces under dynamic wave loads. This research aims to analyze wave-induced soil response and liquefaction risk in the vicinity of an offshore skirted GRP cover. A two-dimensional (2D) numerical analysis is performed using an integrated multiphysics model, implemented in the finite volume method (FVM) based on OpenFOAM framework. Nonlinear waves and anisotropic poro-elastic seabed soil solvers are included in the model. Such parameters as a wave elevation, total soil pore pressure, lifting force (F_z) and drag force (F_x) were verified through grid convergence studies. A parametric study with different wave heights and KC number was realized.
The objective of this study is to explore the dispersion of total (wave- and structure-induced) pore pressure, vertical displacement, pressure gradient, vertical effective stress, shear stress and seepage flow. The results indicate that the liquefaction mostly occurs along the internal skirtfaces and depends on the skirts length. The most severe liquefaction rates are at the moment when wave crest or wave trough is passing the construction. Due to the high initial effective stress the momentary liquefaction at the structure bottom center is insignificant.