Geo-monitoring performed during the construction of the Valík highway tunnels

Abstract

Geo-monitoring (GTM) is an integral part of tunnel construction applying technologies based on NATM (New Austrian Tunnelling Method), the method employed in the construction of most tunnels in the Czech Republic. The correct, exact and timely evaluation of GTM is a decisive factor affecting not only the quality of construction but also its safety and cost-efficiency. The selected geomonitoring range corresponds with the demanding nature of tunnelling work carried out in a complex geological continuum with a thin roof. Monitoring includes both engineering geological supervision, which provides, on a continuous basis, information on rock quality and a whole range of deformation, stress and seismic measurements. In the case of the Valik Tunnels, this basic monitoring was further extended to include automated continual stress measurements in the vicinity of the central concrete pillar. These measurements are still relatively uncommon but they are increasingly playing an important role in observation measurement. The Valik Tunnels provided an opportunity to use the BARAB information system, developed by Stavebni geologie - Geotechnika a.s. (SG - Geotechnika). This system allows the processing, transmission and sharing of a huge amount of information and measurement data. The use of the BARAB system during the construction of the Valik highway tunnels near Plzen proved to be very useful providing immediate access to information, essential for rapid and safe decision-making. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. Reprinted with permission from Elsevier.