Abstract: To fully study the geological adaptability of TBM in SichuanTibet railway tunnel construction, the main unfavorable geological conditions of SichuanTibet railway tunnel are comprehensively analyzed and the adaptability characteristics of TBM are systematically studied. With analysis of the four aspects of geological conditions, i.e. rock burst, large deformation of soft rock, water inrush, and high ground temperature, it is demonstrated that the geological adaptability of TBM construction is weak. The key techniques of TBM construction are described as follows: (1) In the area of rockburst and large deformation of soft rock, corresponding support and construction countermeasures should be taken according to geological prediction and field conditions. (2)For fractured seepage and nonfractured water inrush, the construction of water inrush section can be treated by hydraulic shunt drainage or grouting plugging and reinforcment. (3) In addition to the conventional ventilation physical cooling measures in the construction of high ground temperature section, limited drainage and grouting should be adopted to reduce the amount of hot water gushing in the hightemperature section with rich hot water, and structural heat prevention should be adopted.

Key words: railway tunnel, Sichuan-Tibet railway, TBM construction, unfavorable geological problem, geological adaptability, construction countermeasure