Development of sounding equipment for the assessment of the time- settlement characteristics of recent alluvial deposits when subjected to embankment loads.
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Date
1992
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Abstract
The whole of this thesis is my work unless specifically indicated to the contrary in the text,
and has not been submitted in part or in whole to any other University.
Some thirty years ago the author operated a deep sounding machine, one of the first in
the country, on a misty lake in Ireland and marvelled at the way subsoil information could
be garnered. The magic of the moment never entirely passed and when the opportunity
arose to use the technique in Natal the die was cast.
The development of the national road system surged in the early 1970's and since many
of these roads on the Natal coastal routes crossed extensive recent alluvial deposits, the
geotechnical problems of instability and settlement became major factors in the road
design. Traditional methods of investigation consisted of boreholes with sampling and
laboratory testing. Whilst these were satisfactory, provided they were of adequate quality,
they were relatively expensive if sufficiently detailed models of the subsoil were to be
obtained for design purposes.
Cone penetration testing provided a potential a solution and this led to research work
conducted over a period of twenty five years which continues today. The initial
development of ideas for improvements to the mechanical equipment took place whilst the
author was carrying out preliminary investigations for freeway routes over the coastal
alluvial deposits. This was followed by a period devoted largely to cone penetration testing
research and deVelopment and to embankment design methods at the National Institute
for Transport and Road Research, and to the initial registration for a Master's degree
under the supervision of Professor K Knight in 1975. This research programme was
completed as originally envisaged, but not submitted because during its course the author
conceived the idea of the piezometer cone. This proved to be such an exciting prospect
that the research and development continued for a number of years until piezometer cone
testing has now become almost routine for geotechnical investigations on alluvial deposits.
In 1983, due to Professor Knight's retirement from the University, Mr Phillip Everitt was
appointed as the supervisor.
At that stage piezometer testing was becoming accepted internationally and new aspects
and information frequently appeared. It was apparent, however, that the essential proof
of the system for the prediction of embankment performance was to use it at
embankments where the performance had been monitored. Eventually grants were
provided by the Department of Transport for this, which enabled two research projects to
be conducted during 1989 - 1990 and 1991 - 1992. After completion of the first of these
a presentation of the author's work on cone penetration testing since the mid 1960's was
made to the Faculty of Engineering at the University of Natal. The Executive Committee
of the University Senate subsequently approved, in August 1991, that the registration be
upgraded to doctoral status.
Mr Everitt's encouragement during this extended period has been a vital factor in ensuring
an outcome for this task and the author wishes to express his gratitude for this.
Description
Thesis (Ph.D.)-University of Natal, Durban, 1992.
Keywords
Theses--Civil engineering., Soil penetration test., Soils--Testing, Piezometer., Embankments.