Stadtbahn Gelsenkirchen Mitte, Schalke Nord

In contrast to other cities, Gelsenkirchen finds itself faced with solving the technically interesting task of constructing and operating traffic tunnels within the sphere of influence of coal mines, which are still working. For the tunnels concerned, this signifies they must be able to cope with all kinds of constraining deformations. For dimensioning the construction of tunnels "possible influencing values" are laid down. If these are taken into consideration then the tunnels must be in a position to withstand all loads including deformations resulting from the effects of mining without any damage. In conjunction with the contracting consortium, an open frame for the mobile subsidence trough was created: a steel construction in accordance with the modified "orthogonal-anisotropic yielding resistance principle", which is in the position to satisfy requirements and through plastifications at the points which are subject to the greatest strain, the corners of the frame and in the roof, is capable of evading the attacking forces. As deformations of up to 10 % must be accepted in the longitudinal direction of the tunnel and in the direction of the frame without damage, the props were made of sheet piling profiles - Hoesch System, special steel St. 52.3, whereas the crossbar including the elbows for the sheet piling profiles was formed from cast steel, quality GS 16 Mn 4. Part-sections of the Gelsenkirchen urban railway pass through densely populated areas and require mining means to be applied as buildings often have to be undercut. The routes, which are largely located in cretaceous marl, are suitable for the well-known shield drive and shotcreting with steel supporting methods. In order to ensure that a tunnel structure is able to accept the horizontal longitudinal alterations of the ground resulting from mining activities in the form of tensions and pressures without any danger, active compensatory elements in the form of disc springs were set up in a transverse direction. In a longitudinal direction, it is up to the supporting material itself to contend with tensions and pressures without sustaining cracks or jeopardising the stability. The material steel fulfils this demand most ideally, above all, when its existing versatility is supported by skilful design. Based on the chain of thought which led to the frame-type construction method being used in open excavations, a circular steel tunnel with the exception of the roof section was devised, which is corrugated in a longitudinal direction (accordion principle). The segments are welded together to form 4.80 m sections, transported into the completed shotcreted tunnel via a wheel loader, positioned and welded on to the existing tunnel section.

Country: Germany
Region: Nordrhein-Westfalen
Tunnel utilization: Traffic
Type of utilization: Underground, urban and rapid transit
Client: Stadt Gelsenkirchen
Main construction method: Cut and cover, Trenchless
Type of excavation: Roadheader, Drill & blast
Lining: Steel segments
No. of tubes: 1
Tunnel total length: Gelsenkirchen Mitte: 2 x 88 m single track tubes, 446 m double track tubes, 99 m station; Schalke Nord: length of tunnel 1200 m, length of station 100 m
Contract Volume: ca. 94 mill. DM
Construction start/end: 1974-1982