Robbins Record Breaker finishes up at Moscow’s Massive Metro
On Friday, May 24, the first of threeRobbins EPBs excavating the Moscow Metro made its breakthrough. City officialsand contractors were celebrating not only the early finish, but also the record-breakingachievements of the 6.2 m (20.3 ft) diameter mixed ground machine. The TBMachieved a 37.8 m (124 ft) advance in one day at the end of April 2013 — amilestone for Russian EPBs in the 6 to 7 m (20 to 23 ft) diameter range.
The machine, launched in winter2012, also made excellent rates of 150 m (492 ft) per week and 621 m (2,037 ft)in one month. “The soil condition, crew experience, rigorous schedule,continuous conveyor, and the reliability of the Robbins TBM are all factorsthat helped achieve the record,” said Vadim Bocharov of SK MOST. Robbins FieldService has also been at the site to assist in training of the crew in properoperation and maintenance of the High Performance (HP) TBM with variablefrequency drives. “We can operate the power, thrust, and torque at 100 percent,because that is the benefit of a Robbins machine.” The machine will now bedisassembled in the receiving station site and launched on an additional 1.4 km(0.9 mi) tunnel in the last quarter of 2013.
The machine is just one of severalRobbins EPBs on a massive metro project where dozens of TBMs are operatingsimultaneously. Two 6.6 m (21.6 ft) diameter Robbins EPBs are excavating leftand right-hand tunnels, each 2.0 km (1.2 mi) in length, for contractorEngeocom. A third machine refurbished by Robbins for Engeocom, nicknamed“Julia”, is also excavating a 2 km (1.2 mi) section of tunnel. The machines representthe first time Robbins EPBs have been used in Russia.
Ground conditions in the cityare challenging—consisting of fine sand, gravel, loam, stiff clays and boulders.The EPBs are designed for the conditions, with active articulation to enable excavation of tighter curves without the risk of segmentdeformation. Two-component back-filling is being used to reduce the risk ofsettlement at the densely urban tunnel sites. Mixed ground cutterheadsreinforced with abrasion-resistant wear plate give the option of changing outcarbide knife-edge bits with 17-inch disc cutters depending on the conditions.
Moscow’sMetro Development Program, unveiled in 2012 by the Moscow Government, calls for150 km (93 mi) of new metro lines within the next eight years. Work thus farhas been around the clock, with close to 18,000 workers and specialists engagedin the projects. Their number is expected to reach 35,000 by the end of 2013. In2012 alone, 50 km (30 mi) worth of new rail were built at 69 different sites.
This article wassubmitted by The Robbins Co.
