Performance and cutter life assessments in hard rock tunnelling

Tunnel boring is shown to be a suitable technique method in hard rock tunnelling. Performance, disc cutter consumption and therefore cost are strongly influenced when using Tunnel Boring Machines (TBMs) in hard rock conditions. Furthermore, good predictions of TBM performance and cost facilitate the control of risk as well as avoiding delays and budget overruns. Good rock boreability assessments may be decisive for planning and controlling risk when extremely hard rocks are involved. An ongoing TBM project in particularly hard rock has been analyzed in terms of performances and cutter life assessments. Extensive geological back-mapping, complete rock laboratory testing and gathering of TBM data has been carried out in order to analyze and assess performance and cutter life by using the CSM, Gehring and NTNU prediction models for hard rock TBMs.