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|Title: ||Ground movements associated with trenchless pipelaying operations|
|Authors: ||Chapman, David N.|
|Issue Date: ||1992|
|Publisher: ||© David Neil Chapman|
|Abstract: ||A comprehensive review of the published work is presented
on field, laboratory modelling and theoretical data relating to
ground movements associated with trenchiess pipelaying
techniques. Due to the similarities with convergent trenchiess
techniques, soft ground tunnelling work is also reviewed.
The factors that influence these ground movements are
isolated and the ability to investigate these considered in terms of
model tests. A test facility based on a l.5m long,l.5m high and
l.Om wide steel tank has been developed and this is described
together with the philosophy behind its use. The development of
appropriate methods of simulating both pipejacking and
pipebursting trenchiess techniques using the test facility, based on
the installation of a 200mm diameter semicircular steel pipe
section, are described. The use of a stereo-photogrammetry
technique for the ground movement data acquisition is also
reported and assessed.
Three programmes of model tests were conducted: open
shield pipejacking, closed shield pipejacking and pipebursting.
The test programmes included investigations into the effects on
the soil movements of variations in cover depth, overcut ratio
(pipejacking tests), bursting ratio (pipebursting tests) and the
effect of using different dry sands at different densities.
From the photographs obtained during the tests, the sand
displacements were determined in both the longitudinal and
perpendicular planes to the pipe installation. These displacements
allowed contour plots to be produced for the horizontal and
vertical components of these displacements. This allowed the
interaction of the various areas of sand movement to be
appreciated, and the extents and magnitudes to be investigated
for the changes in the factors made between each test.
The extension of the results to other test conditions not
directly investigated and also to the limited field data available, is
made by using interpolation and extrapolation of graphical plots of
the test data. These graphical plots also allowed trends in the data
to be highlighted. This project involved a fundamental study of ground
movements. However, guidance is given on how the results
obtained from the tests can be used to determine the effects on
adjacent services and structures. This is presented bearing in
mind that the test results were for laboratory model simulations
rather than prototype operations.
Two simple theoretical analyses are described, one based on
the error function curve and one using a fluid flow method. The
error function analysis is used to predict ground movements in
the perpendicular plane to the installation, while the fluid flow
analysis, with dilation and compression capabilities, is developed
to enable ground movements to be predicted in both the
perpendicular and longitudinal planes. The analyses were applied
to the laboratory model tests and the results correlated very well.
The results of the laboratory model tests and the theoretical
analyses developed, considerably extend the understanding and
knowledge on the ground movements associated with trenchless
|Description: ||A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.|
|Appears in Collections:||PhD Theses (Architecture, Building and Civil Engineering)|
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