Stress Analysis of Seabed Using Finite Difference Modelling

Abstract

Coastal structures are always facing the threat of damage caused by different wave actions. A better understanding of different seabed behaviours could effectively reduce the damage caused by waves. In this thesis, four different models (u-w-p, u-p, u and w-p) are developed to analyse the different behaviours of seabeds composed of fine granular soil (silt and normally consolidated clay) and coarse granular soil (loose sand, dense sand, and gravel). In relation to the u-w-p model, which is also the most important and comprehensive one used in this study, acceleration, velocity and displacement were considered, with the three important parameters being analysed: pore water pressure, effective stress, and shear stress. The purpose of this research was to illustrate the general behaviour of various seabeds under wave actions, and to clarify the roles of different seabed soil parameters, then to identify the probability of liquefaction and shear failure for seabed composed of different materials. The research also sought to compare the different behaviour of fine granular soil and coarse granular soil, especially via a detailed description of the behaviour of fine granular soil, and giving a wider picture of seabed response under wave actions, which has not been studied in previous research and could become an important foundation in further analysis of fine grained seabed.