The plate test on clay : a finite element study
The field plate test has been used to derive elastic stiffness
and undrained strength parameters of clay soils. Generally
the interpretations are based on the measurements of the plate
load and settlement, though occasionally additional
measurements have been made in an attempt to improve the
interpretation. The interpretations of soil parameters from
the test rely on simplified assumptions of the soil behaviour.
In particular the soil-is often assumed to be linear elastic
perfectly-plastic. The complexity of the stress and strain
paths induced within the soil by a field plate load test
belies the simplicity of the interpretations.
This Thesis examines the use of the field plate load test as a
method of deriving in-situ parameters of clay soils, using
the finite element method to conduct a parametric study of the
test. The results of these studies have been used to assess
the validity of the parameters determined from the test and
also to examine how the interpretation may be improved.
The Thesis concludes that the interpretation of the plate test
can be improved to yield non-linear elastic parameters of soil
at small strain. In addition the results from a plate test
can, theoretically, be used to predict the elastic load settlement
response of full scale foundations. The test can
also be used to measure consolidation and undrained strength
characteristics of a clay soil appropriate to the
analysis/design of full scale foundations of similar geometry
and load direction.