Abstract:

Taking the construction of Baojiashan extralong Tunnel in waterrich stratum as an example, the author introduces the construction technology for tunnel in waterrich phyllite stratum in detail and develops a rapid construction technology in these geologic conditions, based on "construction technology of threebench and sevenstep parallel production with upward arc heading and core soil". The construction technology for tunnel in waterrich phyllite stratum is described in such aspects as selection of construction schemes and support parameters, determination of excavation methods and types of support system. Compared with the top bench tunnelling method and deformation control by largecross shapedsteel and anchoring cables usually used in tunnel excavation in phyllite stratum in China, the newly developed method combined construction technology of threebench and sevenstep parallel production and advance water controlling technology and radial water controlling technology, has such advantages as easy operation, easy conversion of construction method and rapid construction speed. The construction technology can provide references for similar projects in the future.

Key words:  , tunnelrich waterphyllite stratumrapidconstructiontechnology