Lovat has been busy with its TBMs achieving breakthrough on the Krolsky rail tunnel in Russia, and the Seville metro, whilst securing another order in China for the Chengdu metro.
The 9.5m diameter mixed face TBM completed the 2,250m long rail bore at Krolsky, in east Siberia, which had varied and difficult geology with fissures, fractures and high inflow rates.
Geology along the route comprises slate and granite of up to UCS 250MPa, and blocky sections, as well as saturated loose strata. Inflow varied up to 300m3 per hour.
The TBM (RME375SE Series 21400) will next, as previously planned, be refurbished and upgraded to drive the nearby Mansky tunnel. The 2,500m long drive by the same contractor – Bamtonnelstroy – will parallel an existing rail tunnel. Robbins is also supplying a 4.3m diameter TBM to smaller tunnel for the scheme (T&TI, May 2007, p8).
In Spain, the joint venture of Dragados, Sacyr and Cavosa has completed its last drive for Line 1 of the Seville metro with a 6.05m diameter mixed face EPBM. The JV built two sections of tunnel with a combined length of 4,668m.
Groundwater was up to 15m above the invert as the machine (RME238SE Series 21300) bored mainly through gravel with some sand and blue marls. Best advance rates for the EPBM were 29.4m in a day, 175m in a week and 448m in a month.
In China, the company has signed a contract to supply its third 6.3m EPBM to China Railway Tunnel Group (CRTG) for the Chengdu metro, in Sichuan province. The machine (RME246SE) will be used on Lot 11 of the metro’s Line 2 works.
The contract progress comes through the local steel structures manufacturing partnership between Lovat and CRTG. The EPBM is to be delivered to site in early 2009, and site support will be provided by Lovat China.
The machine will bore geology along the Line 2 route comprising sedimentary deposits, including gravel and cobbles. To minimise abrasive wear, the TBM cutting face and rim will be fitted with chromium carbide plating. The alignment is below groundwater level. Maximum EPB pressure is expected to be 2bar with groundwater varying 6m-13m above invert level.
