Application of Earth Penetration Technology to Ocean Bottom Penetration
Authors: Thompson Louis J. , Colp John L. 
Published: October 2008

The present state of earth penetration technology developed over the past ten years is such that this method can be readily applied to exploration of ocean bottom materials. These techniques permit the remote determination of the in-situ bottom characteristics such as type and condition of sediments, layering, and depth to rock. Experienced analysts can determine, based on the quantitative data obtained from the penetrator, useful information on the engineering properties of the bottom materials.

INTRODUCTION

The bottoms of the world's oceans are rapidly becoming an area of importance to many coastal and ocean engineers. Until rather recently, the ocean bottoms have been of concern only to oceanographers, marine biologists, and marine geologists. Their interests have been mainly concerned with the materials near the water-sediment interface or the underlying geological structures. Engineers in the past have only been concerned with the bearing properties of near-shore areas when constructing structures such as breakwaters, jetties, etc.(1)

In the last decade or so, engineers have rapidly advanced to the ocean bottoms as locations for increasingly complex structures. Many structures such as offshore towers, drilling platforms, under-water storage tanks, etc., have been built. Many others such as deep ocean mining operations, etc., are being planned for future construction.

The need for extensive, detailed information on the physical properties of ocean bottom materials is here today. Ocean engineers can no longer rely on empirical rules of thumb when designing ocean bottom structures of the future. Quantitative measurements of the type, condition, and layering of bottom materials must be made available at reasonable cost.

It is difficult to obtain the needed information from the hostile environment of the ocean bottom. To secure it in the quantities needed and at a reasonable cost, remote sensing methods must be used. Fortunately, the last decade has seen the development of earth penetration technology to the point where it can be directly applied to this problem. Adaptation of penetrometers to the ocean environment can be accomplished quickly to provide the definitive type of information needed. Demonstrations of this capability are now underway at Texas A&M University.

The purpose of this paper is:to describe the present state of earth penetration technology.to outline current research in this field.to propose an ocean bottom exploration system based on penetration technology.to suggest applications for such systems.to encourage other interested persons having such applications to consider the potentialities of this existing technology and to put it to work on their problems.

STATUS OF EARTH PENETRATION TECHNOLOGY

Field studies of the penetration of earth and earthen structures are not new. Past work on this subject has been reported by Robbins and Euler in 1745, by Poncelet in 1829,(2) by Petry in 1910,(3) by the German Army in World War 11,(4) and by several Americans in the 1950's. Of these studies, the work by the German Army group was most notable as they used a projectile designed for earth penetration.