New transport networks for Prague
Prague - Czech Republic
Prague’s inner city is notorious for its traffic jams. However, two major metropolitan development projects are now underway to ease the situation – the Blanka road tunnel complex and expansion of the “Metro” underground railway system. Together, these two undertakings should noticeably reduce traffic volumes in and around the centre of Prague. And the planning engineers and project promoters have opted for product systems from MC to make sure that this is the case.
The Blanka road tunnel complex is currently the Czech Republic’s largest subterranean building project. It comprises two one-way road tunnels with a combined length of around 12 kilometres running under the surface infrastructure of Prague’s downtown district. This ambitious construction project, underway since 2007 and now nearing completion, will be Europe’s longest metropolitan tunnel.
Sustainable waterproofing system
The Blanka tunnel not only features two carriageways for road traffic but also a sophisticated ventilation system and various water drainage ducts. It is being built using both the cut-and-cover and tunnel boring methods. Needless to say, it is essential that the tunnel be reliably sealed for long-term integrity as the build progresses. Consequently, MC injection systems are being used for repairing leaks in construction and expansion joints, and also water-carrying cracks, in line with the stringent requirements of this mega project. With the quality of MC products already widely known, these injection systems were specifically selected by the general contractor and the application companies responsible. The soft elastic sealing injection resin MC-Injekt GL-95 TX, for example, is swellable and thus ideally suited to sealing cracks, voids and cavities, even under conditions of permanent water contact. It also adheres well to plastic waterproofing membranes and is suitable for wide-area curtain injection. While MC-Injekt 2300 plus was used for the repair of water-carrying cracks, it is also suitable for sealing applications in dry conditions. This elastic sealing elastomer injection resin offers an impressively rapid rate of volume increase which nevertheless comes to a halt after an appropriately short time. Both resins are suitable as repair barriers for waterproofing against penetrating moisture.
In the case of water under pressure, the low-viscous elastomer foam MC-Injekt 2033 was injected prior to the permanent waterproofing seal. This injection resin reacts quickly, causing it to foam and expand with a high rate of volume increase. Aside from the road tunnels, the Blanka project also encompasses other structures such as the new Trojsky road bridge, in which the specialty resin MC-Ballastbond 70 is being used for solid ballast bonding and soil strengthening.
These elastic sealing elastomer injection systems are also being used for sealing and repairing the underground station Narodni and the extended Route A underground railway line. While, in the Metro station, water-carrying cracks, voids and cavities, and also (cold) construction and expansion joints of the tubbing elements have required sealing, in the Route A extension, cracks were encountered in the tubbings, as were leakages in the other stations. Wider areas of water ingress are also being injected in the Motol underground station with MC-Injekt GL-95. Special MC services are likewise in demand for this project, with the applicators being trained and supervised as they carry out their work on site.