Abstract:

The Sichuan-Tibet Railway is one of the most important main railway lines under planned and construction of China, and it is an important part of China western transportation system. However, because the railway passes through several big tectonic units, e.g. the Yangtze plate, Sichuan-Yunnan plate, Qiangtang plate and Lhasa plate, under these complex geological conditions, there are some complex geological problems along the Sichuan-Tibet Railway, such as active faults, earthquakes and other geohazards, and thus the planning and construction of the Sichuan-Tibet Railway are restricted. Based on the field geological investigation, geological drilling, analysis of in-situ stress measurements and laboratory testing, the paper analyzes the main environmental and engineering geological problems along the railway, e.g. active faults, high crustal stress, high geothermal activities, rock burst and geodisasters that might occur in the process of railway construction. And the authors deem that there are 54 regional active faults along the Sichuan-Tibet Railway and its adjacent area, and 17 of them are active faults and have directly important effect on the railway construction; the earthquake is frequent in the study area, and 50% of the planning route is located in the area of seismic peak ground acceleration more than 0.2 g, part of the region more than 0.4 g,so the potential seismic risk is likely to happen; the main geohazards are collapse, landslide and debris flow along the railway, most of them are controlled and affected by active faults, and the long run-out landslides are also developed in this area; the tectonic stress and geothermal field are complicated along the railway, and some serious engineering problems are in high risk in the railway construction, such as rock burst, soft rock’s big deformation, and high geothermal calamity.

Key words: Sichuan-Tibet Railway, active fault, engineering geological problem, geohazard, route optimization