Construction Technology of Freezing Holes for a Metro Bypass in Complex Stratum

Taking some subway bypass engineering in Shanghai for example,the technology of ground freezing drilling-hole is described systematically in this paper,which is valuble and of guiding significance for the construction of ground freezing drilling-hole.

Drilling-hole trajectory is the key influencing factor in the construction of metro bypass by horizontal ground freezing method.

Combining the freezing method construction of side channels of the test section of Nanjing subway, authors analyze and conclude some technical problems and countermeasures of the freezing method in different construction stages such as construction of freezing pipes, frezzing, excavation and so fort.

Ground reinforcement of the connecting aisle is finished successfully through strictly controlling key construction measures such as freezing holes construction,freezing station installation and secondary support.

Research conclusions:Taking the connecting aisle construction of bidding 2 of Line 10 of Shanghai metro as an example,the deformation of the ground surface,the expanding and releasing pressures in the soil were monitored on the site and monitored data are analyzed in this paper.

Following a thermal and flue duct resistance calculation,a variety of improvement measures,such as additional provision of a bypass flue duct and an economizer as well as the use of a XD-2000 type gas impulse soot blower,were implemented.