Data report core logging KH-02-2017

Abstract

KH-02-17 is a core drilled bore hole in the upper section of the Åknes rock slope. The bore hole is 300 meter deep, and was core drilled during September-October in 2017. Geodrilling AS performed the core drilling on assignment from Norwegian Water- and Energy directorate (NVE). The rock type registered in KH-02-2017 is gneiss with variation in grain size and colour according to classification from ISO 14689. The core logging shows that the core is intersected with crushed zones in the upper 60 meter. In this section also 6 intervals with core loss are registered. From approximately 60 to 130 meter depth the presence of crushed zones decrease. However RQD- and fractures/meter (FFm) values are varying, but with a trend towards higher RQD values and lower FFm values. From about 130 meter to end of bore hole the rock mass is considered solid with a massive character. Crushed zones are sparsely registered and the rock mass is generally considered good, evaluating RQD- and FFm values. An analysis show high concentration of joints with characteristics corresponding to low friction joints in the upper 150 meter depth. An especially weak crushed zone, with intact silt/clay is located between 69.34-69.65 meter.