Thesis: J.K. Mangal

Doctor of Philosophy, Brasenose College, Oxford University, Trinity Term 1999

Partially Drained Loading of Shallow Foundations on Sand

Summary

Wave loading on offshore structures founded on sand can result in partially drained response. The characteristics of the rate of loading, the permeability of the soil, and the size of the foundation affect the degree of partial drainage.

This thesis is concerned with the effects of loading rate, and consequent drainage, on the behaviour of a flat footing that is founded on the surface of a saturated sand base. The results of physical tests performed in the laboratory on a model-sized footing are reported. The footing was founded on oil-saturated fine sand and was subjected to combined loading. The effect on the vertical, horizontal, and rotational displacements are reported.

The response of the footing is analysed in the context of existing drained foundation models that are based on work hardening plasticity theory. The rate dependency of the vertical load:deformation behaviour and the combined yield surfaces are described.

This thesis can also be downloaded from the ORA website