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Michaelstunnel, Baden-Baden

The existing traffic, noise and fume burden in the heart of Baden-Baden is irreconcilable with a spa and holiday centre and could best be solved by the construction of the Michaels Tunnel. The tunnel circumvents downtown Baden-Baden but in doing so, intersects the main thermal vein, the town's artery. It was thus necessary to examine thoroughly the feasibility of a tunnel. In this connection, a large pilot tunnel was created over the entire length of the proposed drive completed by mining means. Apart from investigating the different types of rock and their geotechnical quality, the main objective was to prove that the main thermal vein could be penetrated without complications arising. During the driving of the pilot tunnel, it emerged that no problems at all arose when penetrating the thermal zone. There were no complications during the drive in technical terms. Furthermore, no water encroached from the thermal zone. This proved that the construction of the tunnel would not affect the resort's baths, and cure activities or the accessibility of the thermal springs. The Michaels Tunnel project with a total length of 2,510 m was divided up into several sub-sections:

Connecting area north: The northern portal together with the air intake plant is located near the old station. The mined tunnel section begins here and stretches over a distance of 1,841 m until it reaches the southern air intake, which is linked up with a parking bay. Apart from a number of parking bays, this section also contains the central exhaust air plant, which transfers waste air from the tunnel to the surface via a shaft. This section was created by bore and blasting.

Oos area: The adjoining section passes beneath the Kurpark with the Oosbach. Cut-and-cover was selected here, although the area is an extremely sensitive one as far as a spa is concerned. In addition, protection of the trees growing there, maintenance of the existing groundwater conditions and negative effects brought on by noise during the planning and execution had to be taken into account.

Connecting area south: The connecting area south of the Michaels Tunnel links up with the inner-urban traffic network around the "Russian Church". In order to accomplish this, the grounds of the former hospital had to be taken over. The design of the portals and the new zone of greenery on the former hospital grounds have placed new accents in urban planning in this district and contribute substantially to the quality of life.


  • Country: Germany
  • Region: Baden-Württemberg
  • Tunnel utilization: Traffic
  • Type of utilization: Road tunnel
  • Client: Stadt Baden-Baden
  • Main construction method: Trenchless
  • Type of excavation: Drill-and-blast
  • No. of tubes: 1
  • Tunnel total length: 2585 m, incl. 806 m cut-and-cover
  • Cross-section: RQ 12 t
  • Construction start/end: 1986-1989 (3 years)
  • Opening: August 1989