Journal Published Online: 01 September 1980
Volume 3, Issue 3

What Constitutes a Turn?

CODEN: GTJODJ

Abstract

There are wide variations in physical configuration and cathead equipment among the available drill rigs used to perform the standard penetration test. Such differences may be partly responsible for variations in blow count among different drill rigs. The paper draws attention to the fact that about half of the available drill rigs use clockwise rotation of the cathead while the others use counterclockwise rotation. Depending on which direction is used, differences in the actual number of turns could be off by as much as half a turn. This difference could result in a substantial variation in the energy delivered to the sampler and in the blow count for the same soil conditions.

Author Information

Kovacs, WD
National Bureau of Standards, Washington, D.C.
Pages: 4
Price: $25.00
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Stock #: GTJ10885J
ISSN: 0149-6115
DOI: 10.1520/GTJ10885J