"Flame VII", the Domestic First Compound TBM for Super Steep Urban Rail Transit Project Was Launched Successfully

On July 20th, the compound TBM "Flame VII" ,remanufactured by CRCHI, started to excavate in the section from Zhuyuan Village Station to Chongqing East Station of Chongqing Rail Transit Line 24 Phase I.

After remanufacturing, "Flame VII" is 82m long with an excavation diameter of 6.86m and installation power of 1750 kw. It is the first TBM used on super steep urban rail transit project in China, and the maximum construction grade can reach to 43‰.

Chongqing Rail Transit Line 24 Phase 1 Project is located at Banan District and Economic-Technological Development District in Chongqing city, with three stations and three sections, which are Lujiao North Station, Kuangjiatang Station, Zhuyuan Village Station, Lujiao North Station-Kuangjiatang Station, Kuangjiatang Station-Zhuyuan Village Station and Zhuyuancun Station-Chongqing East Station. The total length of the line is about 5.4 km. The "Flame VII" started excavate in the section between Zhuyuan Village Station and Chongqing East Station, with a tunnel length of about 2.5 km, and the main geology of the section is miscellaneous fill, sandy mudstone and sandstone. The tunnel roof overburden is 71.7-72.95 meters with "V" slope and 500m curve radius. The maximum grade is 43 ‰. The construction is difficult due to the characteristics of extremely large slope excavation turns and uneven soft and hard strata.

In view of the engineering characteristics of the project, CRCHI has overcome many technical difficulties of the equipment. In order to better control the equipment advancing posture, the equipment can adapt to large slope turning situation and soft&hard uneven ground excavation. CRCHI "Flame VII" compound TBM has been carried out a series of adaptive modification and upgrading measures, which effectively reduces the risk of TBM construction. 

The completion of the project can effectively enhance the north-south transportation capacity of Chongqing rail transportation, which can enhance the radiation range of Chongqing  East Railway Station.

http://en.crchi.com/art/2023/7/20/art_40592_4605514.html