INNOVATIVE SOLUTION FOR THE ASSEMBLY AND INSTALLATION OF PREFABRICATED CROSSCUT CLOSURES IN TUNNEL
Tunnel crosscuts connecting the running tubes are important infrastructural measures to achieve the safety goals for long tunnels. They serve as primary measure to facilitate self-rescue in case of a forced stop in the tunnel. Crosscuts allow the evacuation of people from the incident tube within a short time span to a temporary safe place.
At both end, crosscuts are terminated by walls. Access is ensured by means of safety doors. With conventional methods, the installation and electrical connection of one door in the tunnel takes a well experienced team with three workers around 3 days (based on experience in the Gotthard, Ceneri and Lötschberg Base Tunnel). This results in expensive installation hours in the tunnel, salary surcharges and unproductive travel hours. Since the wall construction is mainly done by the main contractor, accessibility to the crosscut for further installations is limited at an early stage.
Within the SCAUT project ‘Plug-in Crosscut Element (PCE)’, an integral prefabricated push-in wall element for terminating the tunnel crosscut is developed that is immediately ready for use (plug-and-play). The simple but ingenious idea: Prefabricated in the workshop, these fully functional and tested wall systems are delivered to the crosscut in the tunnel with special transport aids and adjusted with low tolerances. Elaborate on-site work, such as for formwork, concrete work, drilling and system installations and assembly, is eliminated. Therefore, installation time can be reduced to less than 90 minutes.
The advantages of such a system solution are evident:
• 15% reduction in manufacturing costs.
• Up to 90% savings in the installation and commissioning time.
• Precise prefabrication of the wall elements in a safe workshop environment.
• Exact measurement and precise pre-assembly of all elements outside the tunnel.
• Extensive testing of all assemblies and systems, such as ventilation units, control cabinets, fire dampers, doors, lighting, signs, etc. (BIM capable).
• High system security through pre-verified modules and components.
• Increased safety through lower personnel requirements in the tunnel. Most work steps can be carried out in the familiar environment of the workshop.
• Full accessibility to the crosscut for further installations up to the last possible point in time.
• Includes RFID technology for rapid component identification.
Basically, this clever system functions in every kind of cross-connecting gallery. A prerequisite for a smooth execution is a corresponding project planning during the shell construction planning as well as a 3-D laser scan of the cross-cut ends. The transport of the PCE in the tunnel can be done rail-bounded in case of a railway tunnel or on a flatbed trailer.
In the following animation video, the fabrication process, the transport and the installation workflow of the PCE is shown step by step.
Starting the project end 2016, a PCE prototype was developed and manufactured in a short time in close collaboration between the SCAUT project partners. On December 14, 2017, the SCAUT consortium under the lead of the Elkuch Group proudly presented the results of the project to a selected audience in the Hagerbach Testing Gallery (VSH). The highlight of the event was a live demonstration of the PCE prototype installation at a scale of 1:1. By that, the proof of concept under real conditions was achieved. The following live video shows a time lapse of the installation process.
As of now, live demonstrations of the PCE are shown at the Hagerbach Test Gallery (booking: https://hagerbach.ch). In addition, the PCE concept is presented by the SCAUT consortium to various interested clients and tunnel operators throughout Europe as well as at the renowned tunneling events such as the Swiss Tunnel Congress and World Tunnel Congress. A first success could already be achieved: Currently the concept is under review and in planning stage for the new high-speed tunnels in Austria.