Abstract: The construction of inclined shafts in highaltitude tunnels within cold regions presents significant challenges, including low air pressure and oxygen levels, considerable temperature variations, and extreme cold and dry conditions. To tackle these issues, a case study is conducted on the Longbagou inclined shaft of a plateau railway tunnel. The authors introduce a mechanized matching principle for inclined shafts, taking into account the surrounding rock grade, section size, and altitude. Consequently, a safe and efficient mechanized construction method is developed, particularly suited for inclined shafts with steep slopes in highaltitude areas. This method involves the selection and deployment of a complete range of mechanized equipment for advance support, drilling and blasting, transportation, spray anchor support, and lining. Efficient construction techniques that include rapid excavation, transportation, and support, alongside swift integration of various processes are proposed. Central to this approach is the management of surrounding rock deformation, around which a proactive support system is constructed, emphasizing early intervention in rock reinforcement, early support, and rapid sealing. The findings reveal that, in comparison to traditional drilling and blasting methods, the advanced mechanized construction, facilitated by a threeboom rock drilling jumbos, significantly enhances construction efficiency (achieving a maximum monthly advance of 180 m, which is 30% greater than traditional methods), improves construction stability, reduces the number of operators required, and ensures appropriate lining strength. Furthermore, the crown settlement and peripheral convergence are maintained within acceptable limits, thereby enabling the rapid excavation, support, and sealing of smallsection highaltitude tunnels.

Key words: highaltitude railway tunnel, inclined shaft with steep slope, drilling and blasting method, mechanized construction; equipment matching