Well proven numerical techniques of analysis have been used to study the manner in which piled foundations deform under working loads. It has been assumed that the soil surrounding the piles may be characterised by suitably chosen elastic constants. This assumption has enabled simple models of the behaviour of single piles under the action of vertical and horizontal loads, to be established; the models have led to more efficient and economic methods of estimating the likely deformation of working piles, and an improved understanding of the manner in which load is transferred from pile to soil. The mode ls for the behaviour of single piles have been extended for the analysis of pile groups by studying the deformation patterns in the soil around a loaded pile. The solutions developed have been extensively checked to ensure that they agree with the results of more sophisticated, computer oriented( analyses, and also that they are consistent with the results of model and full-scale pile tests. An attempt has been made, towards the end of the thesis, to estimate the disturbance due to the installation of a pile, particularly as regards the generation of excess pore pressures and the subsequent consolidation.