OAO “Metrostroy” proceeds with double-track tunnel driving with EPB TBM

On 28th of May, 2014, EPB TBM “Nadezhda” proceeded with its driving of double-track section of Saint Petersburg (Russia) metro line extension in Frunzensky district.

Before TBM was stopped due to technical need of some cutting details replacement, 296 rings (712 meters) had been already installed. The decision on stopping the TBM for its cutting head repairs was taken in the beginning of May as a part of technological process in soft sand and clay soils with boulders and gravel. Previously it was not possible to stop the driving due to the hazardous risk for structures of all kinds in the proximity of the construction site. Survey proved worn-out state of more than 50% of the cutting details. In two next weeks they were replaced.
Along with the driving of the tunnel, construction works for metro stations continue, with ventilation shafts, concrete works and excavation works for halls construction being carried out. Completion date  of the construction remains the same,  2017.