A set of finite element computer programs has been written
for the settlement analysis of structures founded on normally
consolidated and lightly overconsolidated soft clays. The programs
take into account nonlinear material stress-strain behaviour and
creep. Analyses may assume 'undrained' and 'drained' conditions
and fully coupled consolidation analyses are also possible.
The 'modified' Cam clay model has been used with some
modification to model nonlinear material stress-strain behaviour and
a phenomenological creep relationship to model creep behaviour. The
author's programs have been-tested against another, fully tested,
finite element package and also against closed form solutions where
they exist. Sensitivity of the results of creep analyses in response
to possible variations in the determination of the values of the creep
parameters has also been studied.
Results of a combined creep and consolidation analysis of a
flexible strip footing. indicate the relative importance of creep
displacements with respect to the consolidation settlements which are
difficult to separate in practice.
A review is made of the main nonlinear models of soil behaviour
available to the practising engineer. The main techniques within the
finite element method that are used to implement such nonlinear soil
models are also reviewed and the 'initial strain' method chosen for
use in the computer programs developed.
The author's programs have been used to calculate displacements
and excess pore pressures resulting from the construction of a trial
embankment built at Cubzac-les-Ponts in France and compared to the
measured in-situ values. In the conclusions an appraisal is made of the soil model
developed by the author and the nonlinear finite element solution
technique used. Also, the results of analyses using the computer
programs and the accuracy of the results of the analyses of the trial
embankment are summarised.
The author's computer programs are explained and listed in the
form of appendices.
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.