Abstract: A number of innovative tunnel grouting techniques are introduced in the double shielded TBM excavation of Daban Water Tunnel in accordance with the site specific engineering and geological conditions. The liner longitudinal outer displacement stopper, pea gravel backfill grouting for the sealing rings as well as the consolidation grout by using perforated steel grouting pipes are used in the tunnel excavation support. These techniques are based on the characteristics of the large cross section hexagonal liner, pea gravel backfill grouting in the tunnel supporting structures as well as the comprehensive analysis of the construction monitoring data. These techniques significantly improve the excessive displacement of the side liners, lack of required compaction in the pea gravel grouting as well as the problems in the supporting of weak surrounding rock mass during the double shielded tunnel construction.

Key words: Tunnels, TBM Construction, Grouting