Tunnel Valík - The Key to the By-Pass of Plzen
Information about the tunnel Valík, which is a part of construction No. 0510/IB of the Plzen by-pass. This 3.5-km-long construction is the last section from the whole motorway D5 to be put into into operation.
The Tunnel Valík is a part of the by-pass of Plzen on Motorway D5. It belongs to the 3.5-km-long construction No. 0510/IB Cernice - Útušice. This is the only section which is not yet in operation after the opening of both outside 8-km-long parts of the by-pass in December 2003. The price of the construction is estimated at 1,300 mil CZK and the opening date of the construction including a bridge across the river Úhlava is planned for the end of 2006. The by-pass of Plzen and thus the whole Motorway D5 from Prague to border crossing Rozvadov will be complete.
The tunnel, bored like other similar tunnels by the so-called new Austrian tunnelling method (NRTM), ranks with its 380 metres of length into the category of short tunnels. Because of the unfavourable geological characteristics of the hill Valík (435m), designers had to overcome many obstacles during the technical realization of the tunnel. The tunnel consists of two tubes 8.2 m high and 11.5 m wide, bored directly next to each other in order to reach the lowest possible permanent coverage of land, especially near both portals. Each tunnel will have two lanes and one lay-by lane in each direction. The longitudinal gradient of the tunnel is 4%; the maximum height of ground material above the tunnel is 30 metres. Therefore, it will be necessary to strictly follow all prescribed technological instructions during the construction. An exploratory adit was bored in the axis of the tunnel before the actual tunnelling. The adit helped to determine the process of construction works, especially the vertical segmentation of the tunnel. First the middle section will be bored and concreted and later will serve to secure the middle side wall (without a rock pier) for both tunnel tubes. Then side sections of both tunnels will be bored, and, finally, the upper parts of both tubes will be drilled. Secondary (definitive) ferroconcrete walls will be made by a 10-meter-long form, movable on rails.
There are many so far unrealized safety measures at the tunnel, e.g. independent access roads to both portals for vehicles of the integrated rescue system, central safety system, which reacts and evaluates current situation of the operation of the tunnel, etc. In case of an accident, the system automatically calls rescue workers and paramedics. This helps to shorten the time in which they arrive and helps to minimize damage to health or property.
Considering the fact that the tunnel leads through an area of the source of drinking water for Plzen, large number of requirements for the protection of environment were taken into account. All waste water, either from the construction of from the subsequent operation of the tunnel, will be drained into a sump and disposed of ecologically.
The construction was festively commenced on Tuesday, April 4, with a traditional ceremony - a statue of St. Barbara (patroness of miners and tunnel builders) was consecrated and placed into a niche in the western portal. Representatives of designers, representatives of the supplier and journalists were present at the ceremony. The actual boring, however, has already started in January of this year, and 50 metres of the middle section has been drilled up to this day.
An information centre was opened to public at the same time. Visitors can view a visual presentation of the whole Plzen by-pass there, and they can also obtain all information concerning the preparation of the construction and the construction itself. The centre is open every first Friday in the month from 4 PM to 6 PM. It is situated directly at the construction site at the western portal of the tunnel near the town of Štenovice (turn from the provisional by-pass of Plzen, from road No. II/180, 500 metres from the roundbout between Štenovice and Útušice in the direction to Prague). It is possible to provide a technical guided tour for groups announced in advance, even out of official opening hours of the centre.