Abstract:

No.2 karst cave of Yuanliangshan Tunnel on YuHuai railway is located in the Maoba syncline section where there exists rich highpressured water. The longitudinal width of the level profile of No. 2 karst cave is 50m. The water pressure measured under the condition of partial water discharge is 3.013 MPa. Furthermore, the karst cave contains a large amount of fine silt sand. The emphasis of the article is placed on the introduction of the excavation technology adopted in the fullface breakthrough of No.2 karst cave section of the tunnel.

Key words: high water level  , waterrich section karst cave  , tunnel  , excavation technology