Identification of Marine Soils by Ballistic Penetrometry

This article describes a disposable, sensor-filled ballistic penetrator for in-situ measurements during and after penetration into the clayey sediments of the seabed at depths of about 6000 m. The project involved work on several theoretical and experimental aspects of hydrodynamics: penetrator shape optimization, course stability, precision of point of impact. In addition, measurement and data acquisition techniques were developed using high-pressure sensors, and the dynamics of soil penetration and hole-closing were studied. The project led to the implementation of instrument-carrying devices weighing two tonnes, which, by penetrating some 40 m into the clay at impact speeds of the order of 55 m/s, provided valuable information on the physical characteristics of the seabed soils.