Scientific problems and research proposals for Sichuan–Tibet railway tunnel construction

The Sichuan–Tibet railway construction has received significant attention from both China and abroad. The new section from Ya’an to Nyingchi is about 1018.6 km long, including 69 tunnels with a total length of 841.7 km. The longest tunnel (Yigong tunnel) is 42.4 km long. The successful construction of the Sichuan–Tibet railway depends largely on tunnel construction. Due to the complex conditions, tunnel construction for the Sichuan–Tibet railway poses great challenges to the research community. This paper aims to illustrate the necessity of interdisciplinary and joint research to solve problems associated with tunnel construction that will be encountered in the immediate future and facilitate the communication and exchange of ideas between disciplines. To this end, based on a systematic analysis of the available data related to Sichuan–Tibet railway tunnels, six major aspects of the geology, environment, and engineering conditions are identified. Next, based on the engineering responses from the Sichuan–Tibet railway tunnels, potential technical problems and risk characteristics are predicted and evaluated. Further, six key scientific issues are identified and discussed based on a coupled multi-layer analysis of essential tunnel engineering issues. Finally, research directions, technical ideas, and research methods that should be carried out for this project are proposed.