A Research Over Construction Technology For Large Section Shallow-buried Tunnel On Mollisol Tier Of Urban Subway

As the construction speed of Shallow-buried Concealed Tunnel Excavation Works becomes more quickly, it can shorten the time limit for the project construction furthest. It can reduce disturbance to the environmental surroundings (especially the subway projects and city planning projects). It has considerable social and economic benefits. At the same time, the construction technology can be widely used in other mollisol tunnel projects, such as construction in bad geology segments of hydro-engineering tunnel, and so on. With the fast development of Chinese economy, subway construction in many cities is coming to a high peak period. The foreground of subway construction market is considerable. Construction corporations'mastery of this technology will play a very important role in market exploitation.This paper takes【Linhe west station】construction in No.3 subway of Guangzhou as an example. It analyzed and evaluated the construction technology of large section shallow-buried concealed tunnel excavation works on mollisol tier. First, compare the structure projects and choose the right one. Carry on a structure calculation analysis. Then analyze and evaluate the construction technology. Adopt an innovative construction technology. Excavate the middle hole first, followed by the two holes on both sides. So that the three holes can maintains the similar progress. Its core is the Middle column + stairs + CRD surface excavation technology. Because of stratum subsidence and tunnel deformation caused by tunnel construction, take a set of control measures to make the monitor data tend to convergent. Temporary support during construction adopts some integrative technologies, such as large pipe shed , advance-small ducts, grouting anchor pile, bar and the arch, cross steel support and grouting . At the same time, set down a strict construction monitor plan in the construction process. Design a set of monitor system which is integral, comprehensive and fast feedback. The monitor system can be used for bothe information collection and safety forecast.