Abstract:

The basic viewpoint of determination of control technology for tunnel groundwater, interaction between groundwater and tunnel construction, is analyzed. The control technologies for tunnel groundwater should conform to safe construction, no harm to surrounding environment and rational cost and construction schedule. The place, volume, time and timedependent variation of tunnel water inrush are various; as a result, tunnel water inrush should be classified so as to decide proper control technologies. The classification of geological structure and water inrush summarized by Japanese professionals is introduced. The water inrush treating effect should achieve 3 basic standards, i.e. tunnel construction under waterfree conditions, acceptable water leakage conditions or acceptable surrounding environment disturbance conditions, secondary lining without water pressure or acceptable water pressure and rational drainage system behind tunnel lining. In order to achieve abovementioned standards, we should use and improve the waterproof capacity of surrounding rock and pay attention to relationship between water stop and drainage. The control technologies used in China and abroad are introduced. 1) In some criterions, the water inrush volume grade is divided into 3 kinds, i.e. waterfree condition of water inrush volume less than 2.5 L/(min·m), natural drainage when numerous water inrush occurs often and large volume of water burst. 2) Considering water pressure bearing of secondary lining, the tunnel can be divided into 3 cases, i.e. total drainage type tunnel with secondary lining bears no water pressure, nondrainage (waterproof) type tunnel with secondary lining bears total water pressure and tunnel lining bears acceptable water pressure when setting grouting area behind lining. The mountaincrossing tunnels are mainly total drainage type tunnels, tunnels in urban areas are mainly nondrainage tunnels and the tunnels in high groundwater pressure should set grouting areas behind secondary lining. 3) The drainage scheme of water diversion into tunnel and drainage from drainage ditches in China still needs to be discussed, especially in cold regions. The central drainage pipes are set in/under inverted arch and the rain inflow and cleaning water are drainage from tunnel sides in Japan, Germany and France, etc. It is worth studying the drainage scheme. In the end, the author points out that we still have to learn a lot.

Key words: tunnel, mining method, water inrush, groundwater, water pressure, drainage pipe