Unconsolidated Core Sampling

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The ErgoTech procedure, using a thin wall section precision plunge cutting tool is a specific innovation when undisturbed unconsolidated sediment samples are required

The key element of the design is a removable cutting shoe fitted with and expandable collet type plastic core catcher and a precision pre-formed FEP heatshrink liner in a core collection tube.

During the course of the plunging action a small (not normally greater than 2 to 3 bar air pressure) controlled axial stress can be applied to improve the cohesion of the sediment in the plunge cutter as it is not allowed to dilate vertically. The limitation of the technique relates to the grain size distribution of the sediment.

Thus very large grains in excess of Ø1 mm and heterogeneous streaks with small pebbles would cause problems due to the necessary forces exerted on the thin wall tube assembly and the disturbance of pushing larger particles ahead of the cutting shoe.

The available plunging force is probably 10 to 20 times the necessary, so it is that the dimensional stability of the cutting tool is the limiting factor of the technique.

This drawing is copyright (c) and the associated procedure is the property of ErgoTech. It is issued confidentially to parties interested in acquiring the process and to authorised/licensed clients using it. The drawing is not to be reproduced or circulated by any parties without the written consent of ErgoTech which will not be unduly withheld. The drawing must not be mounted on any display boards or reproduced in reports without the written consent of ErgoTech. When permission is granted the reproduction must be identical to the original and the ownership of the drawing and the process embodied acknowledged to ErgoTech by displaying "ErgoTech (c)"