Construction Technology For Subsurface Excavation About Li-Jia Station Of Chongqing Rail Transit Line6

The Lijia Station is the cross-transfer station of Chongqing Rail Transportation6th Line and the new convention and exhibition center extension. The station structure is dual-island, four-line abreast station. Using channel connectivity between the station hall layers to achieve transfer. The maximum excavation section of the station is23.2m×20.06m, and the maximum excavation area is427m2. The rock pillars’spacing between two stations is around6.5m-6.9m. The station is large cross-section and small spacing station. The station uses excavation. The entrance side of the station main tunnel is high backfill accumulation soil slope. The geological conditions are poor. There is no experience can be leant from within the nation, so the construction is difficult.The traditional mining method is adopted to excavate the station. The joint advance support system of ahead of a long pipe roof and ahead of a small duct, the puff anchor composite lining support method, the integrated use of the backfill soil of the portal section of the hole technology, the dual sidewall drift method integrated technology, the cross-section construction, the construction supervision, the large cross-section hydraulic steel lining trolley and other underground construction technologies and processes are adopted.In this paper, according to the actual construction conditions of Lijia Station large cross-section excavation, I summarize the above main construction technologies, and point out the main problems of the station construction. In actual situation, the above technologies are very useful, and the successful experience can be adopted and popularized in other similar projects.