CSR digging machine bores through Chengdu metro tunnel two months earlier

On June 27, mighty rumbles from the 22-meter-deep pumped well on East Square Station of Chengdu Subway Line 2 in Honghe announced that CSR s first metro digging machine had bored through the left tunnel of Section 18 of Chengdu Subway Line two months ahead of schedule, setting a new record in the driving speed of metro digging machines in Sichuan and successfully writing the outstanding achievements of the first homemade metro digging machine.

Chengdu is in a rare structure of water-rich sandy cobble stratum, for which Chengdu CSR Tunnel Equipment Co., Ltd. tailored an earth pressure balance metro digging machine. With a diameter of 6.26 meters, a weight of over 400 tons and a full length of over 80 meters, the machine integrated high technologies such as hydraulic pressure, electromechanical control, laser guidance and control and computer, was delivered to China Railway 23^rd Bureau Group Co., Ltd. CR23g on December 31, 2009, and assumed the task of boring through the left and right tunnels with a total length of 2.8 kilometers in Section 18 of Chengdu Subway Line 2. The 1,398-meter left tunnel was launched this January 2 and open to traffic on June 27. During the construction period, the machine performed noticeably, with a daily driving speed and monthly driving speed of 28.5 meters and 457.5 meters respectively, setting new records in the driving speed of metro digging machines in Sichuan.

According to Li Quanshe, chief mechanic of the Fifth Engineering Company of CR23g, the machine has outstanding performance, no blades were replaced in the full process of driving, and blades were found to be wearing-resistant through post-tunneling inspection. Thanks to the use of mechanized equipment, no safety accidents occurred during tunneling, the working environment of the constructors was favorable, and the construction progress was two months ahead of schedule.

According to the source, the machine will be disassembled and transported to Donghonglu Station for short-term reconditioning, and will continue to serve the construction of the right tunnel of Section 18 of Chengdu Subway Line 2.