Robbins EPB TBM launches at Xi'anThe Xi'an Metro system will service the urban and suburban districts of Xi'an, the 3,100 years old capital of Shaanxi province, and part of Xianyang City. Six subway lines, with a total length of 251.8 km, will be completed by 2020. Lines 1, 2, 4 and 6 will be underneath the ancient city. The 26.4 km north-south Line 2, with more than 23.5 km underground, began construction in 2006, and will be operational in 2011. The 31.93 km east-west Line 1, started in 2008, will be operational in 2013. On the 28.04.2010, China Railway 11th Engineering Bureau Group Ltd launched the first of two 6.2 m-diameter Robbins EPBs on Lot 12 of Xi'an Metro Line 1. The second machine will be launched this month. The Robbins machines will excavate parallel 2.3 km-long tunnels, and will pass through four cut-and-cover stations between Kangfu Road and Chang Lepo. Geology includes sand, pebbles and clay, with significant ground water. Another eight TBMs will be employed to complete the line tunnels. City regulations stipulate a maximum of ± 15 mm surface extrusion or settlement on tunnelling projects, and subsidence and vibration will be carefully monitored. Click cn/46 and visit www.robbinstbm.com. 19/10. The first of two 6.2 m-diameter Robbins EPBs boring China's Xi'an Metro was launched on 28.04.2010