Abstract:

The 255 mlong mined section of Gongbei Tunnel of Hong KongZhuhaiMacao Bridge, crosses waterrich weak stratum and sensitive area of Gongbei Port, is constructed by curved pipe roof + freezing method and fivebench and fourteenstep excavation method. In order to guarantee the smooth construction organization and construction safety, the detail of fivebench and fourteenstep excavation method is introduced from the perspective of site management; the feasibility of the scheme is verified by field construction; and the existing problems, such as crosssection division of some benches, construction sequence arrangement of pilot tunnel, working face arrangement, etc., are put forward. Finally, the idea of excavation scheme and construction organization optimization and the comparison and selection scheme of adding ramp are proposed, and the monitoring results show that： The construction organization adjustment and optimization are feasible, which can ensure the smooth completion of Gongbei Tunnel on schedule.

Key words: Gongbei Tunnel, waterrich weak stratum, pipe roof freezing method, fivebench fourteenstep excavation method, construction organization optimization