Detailed TBM Boring Cycle Estimation Using Rock Mass Rating System
Due to growing importance of Tunnel Boring Machine (TBM) excavation method in tunnelling, tunnel designers require reliable and up-to-date performance prediction models. Most common models consider advance rate as a function of geology and machine parameters. Authors propose an innovative approach: mechanized tunnelling is an industrial process, so whole boring cycle has a substantial impact on performance, depending on type of TBM and from rock mass quality (RMR class). The paper illustrates the potentiality of the model in Brenner Base Tunnel contract “Mules 2-3” case-study. Main challenge in TBM selection and production estimation was considering in boring cycle all stops foreseen in the tender, caused by ground treatment, investigation, excavation of cross-passages. The model allows evaluating TBM advancement and justifying how breakdown have been considered in boring cycle with a systematic approach.