Abstract: The tunnels on SichuanTibet railway have huge works quantity, extremely complex geological conditions and severe climatic features due to high plateau and very cold temperature, resulting in great construction difficulties. In order to do a good job in the overall planning and design of the tunnels, efforts have been paid in a large number of investigations, technology summary of similar projects, and scientific researches. Finally, the new design concept of achieving "using new technologies, attaching top importance to the environment protection and achieving safe and intelligent project" for the tunnels on SichuanTibet railway is proposed, and main design principles are proposed in terms of tunnel alignment selection, option of twin singletrack tunnels vs. option of doubletrack tunnel, as well as selection of crosssection, supporting structure, waterproofing and drainage measures, cold prevention and antifreezing measures, disaster prevention and rescue measures, construction machinery matching mode, construction ventilation and oxygen supply mode, spoils and environmental protection mode, advance geological prediction mode, and construction organization which can provide technical support for the planning and construction of the tunnels on SichuanTibet railway.

Key words: SichuanTibet railway, tunnel, design principles, design concept