2012 Volume 8 Issue 1 Pages 25-30
Drilling velocity and impact energy are usually used in the exploration drilling system for the geological prediction. The authors, however, propose the new drilling parameter named “Normalized Drilling Velocity Ratio" for evaluation of geological characteristics ahead of the tunnel face, using conversion analysis based on non-core drilling parameters. This new parameter, enable to neglect the change of feed pressure which gives large effect to the evaluation of other drilling parameters, is suitable for engineering classification of tunnel ground and also for detection of fault zone. Additionally, we propose the new calculation method of competence factor in the tunnel ground, which is one of the index for judgement of squeezing ground, using “Normalized Drilling Velocity Ratio". We have already studied the relation between the new drilling parameter and geological condition in Japanese tunnel excavations and close relationship between them. In this paper we show the fundamental concept and outlines of the new analysis system for exploration drilling system.
