Applicability evaluation of a new quantitative rock mass classification for deep shaft, 1; Sedimentary rock

Kuji, Masayoshi*; Asai, Hideaki; Matsui, Hiroya 

Two deep shafts (the Main Shaft and the Ventilation Shaft) at The Mizunami Underground Research Laboratory (MIU) is currently being constructed by Japan Atomic Energy Agency (JAEA). To estimate the rock mass quality and UCS on shaft wall, existent rock mass classification methods (CRIEPI, RMR and New-JH) and in-situ needle sounding tests were applied in rock. A new quantitative rock mass classification method based on JGS standard was developed. This method showed good suitability to sedimentary rock in the Ventilation Shaft. Afterward, the new method was applied to heterogeneous sedimentary rock in the Main Shaft.