关键词: 地铁, 折返线, 隧道, 矿山法, 竖井

Abstract: The Changsha Metro Line No. 3 is a subway line that has in operation. The underground excavation and turnaround section of the Dongtang Station is a double track large-span length section constructed by mining method. Along the tunnel alignment, there are dense distributed buildings in the surrounding area, and there is no convenient site to set up vertical shafts to create working faces. The top of the tunnel is close to highly permeable pebble formations, and the geological conditions are poor. After a detailed on-site survey, the vertical shaft was finally chosen to be in the middle of the road, avoiding roadside trees. The enclosed area is narrow and small, making construction difficult. The side is adjacent to a parallel synchronous excavated and shielded tunnel, which belongs to a high-risk tunnel project in the bustling area of the city center. The vertical shaft half rode over the mining method excavated tunnel, carefully optimizing the excavation and backfilling plan of the tunnel vertical shaft, handling measures for the parallel excavation operations adjacent to the shielded tunnel and briefly describing the emergency of the water leakage risks in the vertical shaft and underground excavation. Finally, overcoming difficulties, the implementation of the underground excavation tunnel was successfully completed, providing a good reference for the similar construction projects in the future.

Key words: Subway, Turnback Line, Tunnel, Mining Method, Vertical Shaft