China is planning to construct 2500 km of underground train lines in 23 towns by 2016.
The Huasuitong company or the art of boring tunnels
The Huasuitong company, part of Tianye Tolian based in Qinhuangdao (300km east of Beijing), manufactures TBMs (Tunnel Boring Machines) with a round cross-section for different earth types. The machines used to construct tunnels for the various underground train lines in China (in Beijing, Wuxi and even Fuzhou) are EPB (Earth Pressure Balance) type. This type of TBM is designed to bore through earth with less than 7 bars of pressure and is capable of containing the earth while balancing the earth and the pressure.
For the future underground train line in the town of Fuzhou running from Baihuting to Huluzhen over a distance of 1083 metres, the TBM is 6.3 metres in diameter and progresses at an average speed of 14 metres per day.
High-performance motors to drive the cutting head
To drive the cutting head, the Huasuitong company has chosen Leroy-Somer’s watercooled SLSHR motors. Thanks to their robust design, SLSHR motors can cope with the demands of extreme environments. They have numerous advantages: compact size, reduced noise level and energy savings resulting from their high efficiency, not to mention the possibility of variable speed operation without derating or external fan.