Following the launch of the 'Peony No. 1' shield machine on Metro Line 1, good news has arrived again—the second shield machine has officially begun hoisting and is scheduled to start boring on March 20. The third shield machine is planned to start boring on April 20, meaning the city's metro construction will enter the 'double-tunnel' boring phase.
　　1 Electric Drive: Second Shield Machine 'More Powerful'
　　At the shield launching area at the east end of Shijiawan Station, the reporter saw that five trolleys of the second shield machine had been put in place.
　　The project manager from the contractor—Sinohydro Bureau 7—introduced that the structure of this shield machine is similar to that of 'Peony No. 1', with a total of six trolleys, each nearly 11 meters long. Including the shield body, the fully assembled machine is 84 meters long. Inside the trolleys, there are also five muck cars, one mortar car, and two segment cars. After the cutterhead, body, and tail are assembled, the shield machine weighs at least 400 tons, and its working area is at least 17 meters below the surface.
　　'The only difference is that this shield machine is electrically driven, while 'Peony No. 1' is hydraulically driven,' the manager said. This is mainly because the geological conditions in its operating section are more complex, mostly cobblestone strata, requiring greater boring power, and the electric drive can meet the boring needs of this area. Just like a car, electric drive has 'larger displacement and more horsepower' than hydraulic drive.
　　2 Operating Section: Shijiawan Station (East) – Yangwan Station. As is well known, Shijiawan Station is the first station in Luoyang where shield boring began, with the section from Shijiawan Station westward to Tawan Station. The second shield machine is still launched from Shijiawan Station, but its boring section is from Shijiawan Station eastward to Yangwan Station.
　　This section is about 1.6 kilometers long and is the last of the 18 stations on Metro Line 1. After completing this section, the shield machine will continue eastward for 1.1 kilometers to the Chandong Depot. 'This section is the logistics support area for future metro vehicle scheduling, maintenance, and repair, and will be built concurrently with the metro track,' said a relevant person in charge from the Municipal Rail Transit Company.
　　3 Construction Schedule: 'Double-Tunnel' Boring to Start Around April 20
　　Metro operation has outbound and return trips, so metro construction involves parallel double tunnels. Taking the section from Shijiawan Station to Tawan Station as an example, the south tunnel was bored first, and after it was completed, the machine turned around to bore the north tunnel.
　　The section from Shijiawan Station to Yangwan Station is different; it will mark the beginning of the 'double-tunnel' boring mode in the city's metro construction.
　　According to the construction plan, the second shield machine will be fully commissioned today and start boring on March 20; the third shield machine is scheduled to begin hoisting on March 8 and start boring on April 20. By then, the section from Shijiawan Station to Yangwan Station will become the first 'double-tunnel' boring section on Metro Line 1. (Luoyang Evening News reporter Lian Yi, intern Nie Fei, correspondents Mu Yansong and Ma Yujun / text; reporter Du Qing / photo)
　　All 18 Shield Machines to Be Operational by Year-End
　　Metro Line 1 runs from the western end of Zhongzhou West Road in the west to the extension of Zhongzhou East Road in the east, passing through Jianxi District, Xigong District, Laocheng District, and Chanhe District. The line is 22 kilometers long with an average station spacing of 1.3 kilometers, and has 18 stations including Gushui, Qinling Road, and Wuhan Road, all of which are two-level underground stations, with a total of 119 metro entrances/exits.
　　A relevant person in charge from the Municipal Rail Transit Company introduced that 18 shield machines will be used for the entire Metro Line 1 project. These machines will gradually be put into operation this year and all will be operational by the end of the year, laying a solid foundation for the completion of tunnel boring on Line 1 by May 2019.