t in situ where the installations are to be located, comprehensive data acquisition is required in the entire area affected and far down beneath the sea floor. Such processes that encompass offshore site investigations are varied in nature. They range from analyzing marine geological information, scrutiny of available geophysical data which is used to plan the actual investigations. Such processes that lead to the success of the above mentioned range consist of drilling, sampling as well as in situ testing which in essence includes penetrating into the seabed with the help of high technology drilling vessels. These processes encompass what is generally referred to as Geotechnical investigation.
From The period 1985 to 1982 Lunne and Powell (1992) gave a review of developments in offshore investigations. They explored the various technological inventions that marked this period and discus the contributions of such developments to offshore studies with new in situ tests being tried out in the offshore environments, including several examples of field model testing. Lunne and Powell observed the general trend over the last 6-8 years which was the gradual increase in deep water developments. Due to the difficulty of taking undisturbed samples in deep water there has been a tendency to rely more on situ testing. Special geotechnical problems associated with geo-hazard evaluations have also inspired developments within the field of in situ testing. In addition the general competitiveness of the market has been a driver cost efficient solutions.
Borings, the most efficient and probably accurate technique of shallow offshore studies come in two main varieties, large-diameter and small-diameter boring. Large-diameter borings Peres involve offshore drilling with large enormous machines that bore extensive areas. They are rarely used due to safety concerns and expense, but are sometimes used to allow a geologist or engineer to visually and manually examine the soil and ...Show more