Numerical investigation of the behaviour of embedded mooring chains and the development of trenching

This thesis addresses two geotechnical issues associated with offshore mooring chains: (i) embedded chain behaviour for catenary moorings and (ii) the development of 'trenching under cyclic loading for semi-taut moorings. Both are explored for undrained loading conditions by performing large deformation finite element analyses. The work provides new insights into chain behaviour in terms of the 'operative' axial friction of the chain and consequently modifies current design methods. Furthermore, it improves the understanding of 'trenching' by viewing the kinematics of different parts of the chain and how this affects gap formation and remoulding on a quantitative basis.