The STUVA Conference 2017, the International Forum for Tunnels and Infrastructure, will take place on 6 to 8 December 2017 in Stuttgart. At this „family meeting of the tunnelling industry“, you can...
focusing on “Excavation and Support in Soft Ground Conditions”. Some of the best specialists and experts of tunnelling in the world took their time to present and share their knowledge with an international audience of roundabout 60 people (some 15 young professionals and students from WTC host country Norway).
The new ICE high-speed line between Wendlingen and Ulm, just on 60 km in total length, is currently under construction in the south-east of the Stuttgart metropolitan region as part of the expansion of the pan-European high-speed rail network. A further major project – the around 8.3 km long Albvorland Tunnel near Kirchheim unter Teck – has recently been started, and is the final tunnel-construction project, closing the remaining gap between Stuttgart and the Swabian Alb. Maximum safety is also needed for this project, with overburdend varying from a maximum of 65 m to a minimum of only just on 9.50 m and head of water of up to 45 m. This enhanced safety awareness was also reflected in the technical schedule of works for the segment seal in the context of the project tendering stage.
Test Procedures for the Assessment of Durability under Sulphate Exposure
Until now, segment-lined tunnels in low mountain formations have been constructed with one layer of pressure-tight lining, with sealing being provided by elastomer gasket profiles. The application limit of this method of construction is about 5 bar. If the water pressure is higher, a much more elaborate and thus more expensive double-shell construction with an additional drainage layer between the inner and outer lining is necessary. In the recent past, a solution for this problem in mechanised tunnelling with segment lining has often been discussed in the specialist world: a drainage layer of permeable material for annular gap grouting. This would then make the installation of an additional inner lining with drainage layer no longer necessary.
The tunnel below the A8 federal motorway is located on the Swabian Alb plateau, which is intersected by the new Wendlingen–Ulm high-speed rail route. Reports on the major project and the plan approval section (PFA) 2.3 Alb plateau have already appeared elsewhere in the magazine tunnel. The tunnel lies close to the highest point of the route, in the third route section of the roughly 21 km long plan approval section.
When space is scarce in the big cities, construction targets the “third dimension”. This has been the case for quite some time now. Modern high-risers have been featured in urban centres in conurbations since the mid-1800s; the first skyscrapers appeared almost 100 years ago. However, the Swiss SCAUT initiative established just a few months ago is not directed sky high: “The third dimension after all, also leads in the other direction – down below”, as Felix Amberg, the president of the SCAUT development association maintains.
On the morning of 12 August 2017, water and earth collapsed into the east bore of the Rastatt Tunnel in the course of construction works. The permanent way and tracks of the Rheintalbahn (Rhine valley...
In connection with tunnelling injections are executed with different goals in mind. An important objective in this case is sealing the rock immediately bordering the tunnel with the aim of preventing water being conducted along the tunnel shell. This is of particular significance if layers of rock which carry water as well as layers sensitive to it have to be penetrated, because the water must be prevented from being transported to the sensitive layers. Injections for sealing rock are also needed if the tunnel is partly produced with a closed invert and partly with an open invert or if waterproofing structures are required to prevent longitudinal conductivity. This report deals with the suitability of injection agents for the cited purpose.
More than 15 km of the tunnels for the Stuttgart–Ulm rail project located in the Stuttgart urban area lie in gypsum keuper containing anhydrite, which swells in contact with water. Owing to the swelling pressures that occur and the displacements caused by swelling, major damage has resulted in the case of many tunnels in the past. As a consequence, the corresponding sections of the tunnels in the Stuttgart urban area are driven absolutely dry.
Digitalisation in construction leads to a decisive advance: according to studies, up to 57% of the work performed in the construction process still has no added value, caused by mistakes and defects, waiting and search times, poorly coordinated sequences and lack of communication. With digitalisation, it should be possible in the future to exploit this potential, enabled by the use of innovative technologies like Concremote. The sensor solution from Doka delivers data of the temperature and strength development of concrete in real time.
