【Domestic News】The "Jiangcheng Pioneer" TBM goes offline to build a single-hole double-track underwater tunnel of Wuhan Metro
On December 15, 2021, Lot 1 of the PPP project of Wuhan's first Metro loop line - Line 12 (Jiangbei section), undertaken by China Railway Tunnel Group ushered in an important milestone: The "Jiangcheng Pioneer" TBM "customized" for Wuhan Metro Line 12 under the Yangtze River went offline in Jiangxia District of Wuhan City. The new TBM will be put into future construction of the river-crossing tunnel between National Expo Center South Station and Lingwucun Station of Wuhan Metro Line 12.
Super-large diameter domestic TBM is customized for crossing the Yangtze River
The "Jiangcheng Pioneer" TBM is jointly developed by China Railway Tunnel Group and China Railway Engineering Equipment Group. The excavation diameter of TBM cutterhead is 12.56m, which is equivalent to the height of four floors, and the excavation section is four times that of conventional metro TBM. The total power is about 7000 kW, which is equivalent to that of the famous “Harmony” bullet train; The overall thrust is about 16,000 tons, which is 11 times that of the “Long March 5” carrier rocket. The whole machine weighs 2900 tons and has a total length of 105 meters, making it a real "infrastructure dragon".
The section from National Expo Center South Station to Lingwucun Station extends 3.37 km, 70% of which goes underwater. It is the control project of the whole line of Wuhan Metro Line 12. The "Jiangcheng Pioneer" TBM will open a river-crossing tunnel for two opposite metro trains at the bottom of the river with an average water depth of 34.85 meters.
CRTG Tackles the worldwide challenge of long-distance underwater tunnel.
The construction of long-distance underwater tunnel has always been a challenge in the tunnel and underground engineering industry. In particular, the difficulties such as super-large TBM diameter of 12.56m, mudstone stratum with exceeding 50% soil quality and ultra-high water pressure are intertwined, which highlights the extreme difficulties of the project.
The "Jiangcheng Pioneer" TBM adopts atmospheric-pressure composite cutter-head. Based on the geological conditions of mudstone stratum with exceeding 50% soil quality, it increases the opening rate to effectively reduce the risk of mud cake formation. At the same time, it is equipped with new technologies including automatic pressure compensation, four circuit pressure maintaining and high-efficiency mud circulating slag discharge system. By improving the cutter-head circulation system and installation of high-pressure water knife device, the slag discharge capacity of the cutter-head is enhanced.
Once the Wuhan Metro Line 12 is completed, it will effectively enhance the attraction of loop line passengers, alleviate the passenger flow pressure in the central area, and open a new era of accelerating the development of Wuhan Metro and achieving whole metropolitan area in one loop. It is of great significance to accelerate the construction of key urban areas and improve the urban comprehensive transportation system, and make new and greater contribution to the infrastructure construction and economic and social development of Wuhan.