Evaluation of Geological Characteristics Ahead of the Tunnel Face Using Both Conversion Analysis of Non-Core Drilling Parameters And New Parameter “Normalized Drilling Velocity Ratio”

Abstract

The authors propose the new drilling parameter named “Normalized Drilling Velocity Ratio” for evaluation of geological characteristics ahead of the tunnel face, using conversion analysis of non-core drilling parameters. This newparameter, enable to neglect the change of feed pressure which gives large effect to the rock evaluation, is suitable for rock mass classification and also for detecting of fault zone. We showed the relation between the new drilling parameter and tunnel rock mass classification using tunnel excavation data, and also discussed relations among the parameter, geology, groundwater, deformation, and construction methods.