The acquisition of marine survey data is traditionally undertaken from surface vessels including
boats and temporary rigs. Translation of these techniques to the nearshore zone is a complex task
and requires equipment adaptation and. often the sacrifice of data coverage. The remotely operated
vehicle (ROV) offers the potential for overcoming some of the standard nearshore survey Concems,
providing remote intervention and data acquisition in areas of restricted access.
In situ testing is the most efficient and reliable method of acquiring data with minimal sediment
disturbance effects. Research has been undertaken into the viability of nearshore cone penetration
testing (CPT) which has shown the T-Bar flow round penetrometer to be a possible solution. Data
could be acquired in sediments with undrained shear strengths of up to 300 kPa from a bottom
crawling ROV weighing 260 kgf and measuring 1 m in length by 0.6 m in width. The collection of
sediment cores may be necessary in areas requiring ground truthing for geophysical or in situ
investigations. A pneumatic piston corer has been designed and manufactured and is capable of
collecting sediment cores up to 400 mm in length, 38 mm in diameter, in sediment with undrained
shear strength of 17 kPa. To ascertain additional sediment characteristics in situ, a resistivity subbottom
profiling system has also been designed and tested and allows for discrimination between
sediment types ranging in size from gravel to silt.
The integration of equipment and testing procedures can be fiirther developed through the use of
integrated data management approaches such as geographical information systems (GIS). An offthe-
shelf GIS, Arclnfo 8, was used to create a GIS containing typical nearshore data using the Dart
estuary as a case study location.
Date of Award | 2002 |
---|
Original language | English |
---|
Awarding Institution | |
---|
THE ROLE OF THE ROV WITHIN INTEGRATED GEOTECHNICAL AND HYDROGRAPHIC SITE INVESTIGATION
GILLON, R. J. B. (Author). 2002
Student thesis: PhD