Mosmetrostroy Contractors of Moscow, Russia have arranged the purchase of a specialised 11m diameter EPB machine from Lovat capable of a 100m radius vertical turn that is to be used to excavate 150m long escalator tunnels at slopes of 30°.
The agility of the TBM is due to twin articulation joints (passive and active) and a cyclical copy cutter. Once each short length has been tunnelled, the TBM has further been designed for disassembly and transport back through the newly constructed tunnel.
The tunnel alignments are below the water table at a maximum depth of 80m above the tunnel invert. Geology is anticipated to comprise carbonate rocks and various soil groups, including clay, loam and loamy sand. Spoil transport will be by high density pump. Lining will be by way of 6 no. precast concrete segments plus a key. The lining o.d. is 10.6m and i.d. is 9.4m.
The mixed face cutterhead will feature abrasion resistant plating on the face and rim, ripper teeth that are interchangeable with disc cutters, scraper teeth and six independent injection ports for ground conditioning.
Lovat is also supplying a design for the segmental lining, segment forms, technical support for commissioning and operation, together with guidance systems, ground conditioning and grouting equipment. Purchase terms were finalised in September, with delivery due in September 2007.
Earlier in the year, Lovat told T&TI how it had been contracted to design and supply a turnkey segment plant in Russia for Chelyabinsk. The scope included designs for segment moulds.
The moulds have been tested and accepted by Chelyabinsk and the programme to have the automated segment plant ready for full operation by the year’s end should be met.
