TBM Performance at Nedre Røssåga

Abstract

Tunnel Boring Machines are back in Norway after a 20-years break. Many expectations are linked to the return of TBM. A Robbins main beam TBM is excavating a head race tunnel at Nedre Røssåga.Originally a probe drilling system was to be examined, but was never performed at site during working with the thesis. Therefore a theoretical part is included in this thesis with a brief discussion on exploiting established systems for probe drilling in TBM tunneling. It is suggested methods to predict performance from both NTNU and CSM prediction models. Also some suggestions on neuro fuzzy methods can be applied.The thesis is based on a literature study, field study and laboratory study. Data are acquired at the job site by the author. The field study and laboratory study are basis for a review of the NTNU prediction model.The laboratory tests used in NTNU model are performed and investigated as it was suspected that the boring process had impact on the rock samples. Disturbed and undisturbed samples from four different locations in the tunnel with representative geology have been tested and compared. It seems that the boring process have impact on the Brittleness Value, but in less than assumed. From field data the actual performance of the TBM at Nedre Røssåga are examined. The NTNU model and FullProf have been used to predict performance. Through comparisons between actual and predicted performance, it is likely to say that the NTNU prediction model performs well for the Nedre Røssåga project. It is shown that the impact of the fracturing is the most important parameter, as stated in existing literature.Cutter wear and life is also predicted well in homogenous rock mass, but weaker predicted in fractured rock mass.