China Railway Engineering Corporation (CREC) Bureau 5 is celebrating the breakthrough of its tunnel boring machine on the final 2.3km section of the Line 6 metro in Beijing, China.
The 6.15m diameter Robbins earth pressure balance machine completed the final drive on the 12km Line 6 extension in less than three months.
Ground conditions on the final section were challenging with loose, soft ground, as well as fine sands, and contractor CREC injected bentonite ahead of the cutter head to overcome the problem. The tunnel also passed within 1.5m of a high voltage cable and below a 30m wide river, which added to the challenges on this final tunnel section.
Work is now underway on the fit out stage of the project, which will enable the seven new stations to open in September this year. Further extension of Line 6 is planned that will extend the line to 54km and work on that is expected to start next year.