New railway tunnel for increased traffic load
Eastern Carpathian Mountains - Ukraine
The Beskyd tunnel in Western Ukraine is an important link for railway traffic between Ukraine, Hungary and Slovakia. However, because of its single track and rather dilapidated state, it significantly restricts the traffic flow of the otherwise two-track route, making it a real bottleneck. Now a new tunnel is under construction, for which both the client and the contractor have placed their faith in the concrete know-how and proven products of MC-Bauchemie.
Passing through the Eastern Carpathian Mountains, the Beskyd railway tunnel has been in operation since 1886. As it is used by around 40 percent of Ukraine’s transit railway traffic, it is a particularly important asset. In order to be able to successfully cope with the significant increase in traffic volumes expected for the future, a parallel tunnel tube has been under construction since 2011 under the auspices of the national railway administrative authority “Ukrzaliznytsya”. With overhead rock extending to heights of up to 180m, it has a specified length of 1,822 m (including portals), a height of 8.5m and a width of 10.5m. It will contain two tracks and allow speeds of up to 70 km/h, almost double the value currently possible in the old tunnel. The two tubes will be connected by three cross-galleries so that the old tunnel can be used as an emergency escape and rescue route.
For the implementation of this project, the building contractor “Interbudmontazh” Construction Association is relying on the technical and process expertise of MC-Bauchemie, which was able to convince the customer with its tailored products, high level of service and the rapidly organised production and supply of the necessary admixtures.
Fast and cost-efficient application
The tunnel is being blasted through the mountain, with the resultant cavity being stabilised with shotcrete. At the suggestion of MC’s concrete technologists, the ready-mix provided as the basic material for the wet spray process has been formulated with the superplasticiser MC-PowerFlow 2695 and the setting accelerator Centrament Rapid 640.
MC-PowerFlow 2695 is based on the latest MC polymer technology and, with economical dosage levels, enables the production of stable, segregation-free concretes of minimal adhesiveness to greatly facilitate and accelerate the placement process. The admixture also promotes the development of high initial strength in the concrete. The added shotcrete accelerator Centrament Rapid 640 is specifically suited to stabilisation applications in tunnel and mining work, scoring big with high initial strength values, low dosage levels and minimal bounce. Because of the possibility of placing layer thicknesses of 15 to 20 cm per pass, it also facilitates rapid tunnel heading progress.
Both products are thus currently serving to promote fast and cost-efficient tunnel stabilisation work ready for the actual lining, for which the admixtures have yet to be specified. The tunnel is scheduled for completion at the end of 2017, by which time it will have absorbed around 82,000 m3 of concrete. Commissioning of the tunnel is expected to take place in the following year.