| Summary: | The thesis considers the problem of vertical pile group response
to lateral static loads. There are various solutions available
for single pile response to lateral loads. These solutions have
been verified against a large database obtained from field
experiments and model experiments. For pile groups very few
theories have been proposed and due to the comparatively smaller
database available it is not possible to develop and test a
sound theory for predicting the pile group response to lateral
loads.
This thesis is aimed at obtaining a database for response
of pile groups comprising of two piles subjected to lateral
static loads. Tests were carried out in the Hydraulic Gradient
Similitude Device in order to bring the stress state in the soil
to the field stress level. For testing purposes three cases were
considered, single pile, single pile adjacent to a loaded pile,
and a pile group of two piles.
The single pile test results showed that the test results
were repeatable and reliable. The tests on a single pile
adjacent to a loaded pile showed that the position of the pile
with respect to the loaded pile has a strong influence on the
response of the pile. The unloaded pile in the direction of the
loading and in front of the loaded pile is most effected. At a
spacing of 2 diameters bending moment developed is up to a
maximum of 20 percent of bending moment developed in single
pile. This percentage decreases rapidly with increasing
spacing. If the unloaded pile is located behind the loaded pile
or is at 90° to the loading direction, it essentially picks up
very little load from the loaded pile. The installation of two
piles densities the soil in between.
In case of pile groups, the load sharing among the piles is
based on the pile location and the interaction effect is not
reciprocal. The lead pile, i.e. the pile in the direction of
load, shares maximum load with trail pile sharing smaller load.
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