Abstract: This paper presents a case history of using the blasting borehole drilling information to predict the geological conditions in rock mass with various rock qualities. This inhouse developed system records the penetration rate of the blasting borehole drilling in the tunnel excavation. The results indicate that the borehole drilling penetration rate is closely associated with the rock mass quality class and the higher rate relates to the poorer rock mass quality. Therefore, the borehole drilling penetration rate can be used as an index for determining the rock mass quality. The results also show that the change in the penetration rate might be related to the fissures in the rock mass. Higher penetration rate relates to the well-developed joints and fissures in the rock mass.

Key words: geological condition forecast, blasting borehole drilling, drilling penetration rate, rock mass quality