TBMs: Capabilities, Limitations and Challenges

The Tunnel Boring Machine (TBM) technology has significant advantages over conventional Drill & Blast method, and it has become one of the most common tunnel excavation methods in the world. However, weaknesses of TBM such as the poor adaptability to complex geological conditions create a bottleneck in its functionality, and restrict its further development. Therefore, factors such as engineering geological conditions, construction schedule, cost, environmental impact and other multi-disciplinary influences should be well considered in the TBM selection. This paper presents the capabilities, limitations and challenges of TBM method by a study of various case projects, and proposes effective countermeasures towards bad geological conditions. The results of this research are helpful for improving the TBM working efficiency and ensuring a smooth and safe construction.