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Heidkopf Tunnel - German Unity Tunnel

The Heidkopf Tunnel - one of the Germany Unity Traffic Projects - passes beneath the Heidkopf heights and beneath the border between Thuringia and Lower Saxony, until 1990 the border between the GDR and West Germany. As part of the A38 between Göttingen and Halle the 2 parallel running tubes at a centre distance of 22.5 m are being driven by trenchless means given overburdens ranging from approx. 7 to 29 m. Each tube possesses 2 lanes and emergency footpaths at both sides given an overall width of 9.50 m. The gradient runs in a knoll, with the longitudinal incline at the west portal equalling 3.2 % and the one at the east portal -1.36 %. The 2 bores are linked to one another by 5 cross-passages (2 of which can be used by vehicles). In addition, each tube - in each case at thirds of the way along - is provided with two 70 m long lay-bys. Both drives were excavated from west to east by drill+blast and excavator. The shotcrete outer shell and the permanent lining are separated from the watertight concrete that was used only by an air cushion foil and a geotextile on account of how the permanent lining was executed. Any underground water present is collected in wall drainage systems at the foot of the verges and transferred unpressurised to the portals. Stable slotted PE pipes with white, coextruded inner shell as signal layer were electro-welded at the joints and enveloped with cement-bonded drainage gravel. The tunnel is located to the east of the Leinetal Graben in the Eichsfeld Scholle and in the west crosses the Solling and Detfurth Sequence of Middle Mottled Sandstone. The official start of work on the 2 tubes was celebrated at the subsequent west portal on March 23rd, 2004. By January 17th, 2005, the crowns of the 2 drives for the Heidkopf Tunnel had each been excavated from west to east over a length of 1,600 m at an average rate of advance of approx. 5.60 m per working day. On January 17th, 2005, a cave-in of roughly 140 m³ occurred in the crown of the southern tube during tunnelling Operations at tm 1,620. The stabilisation measures that were then required led to the driving operations temporarily coming to a standstill. Following subsequent exploration of the geology of the section that still had to be driven by means of 2 horizontal core bores, it was decided to drive the remaining 60 m or so of the southern tube with a considerably smaller cross-section. As a result, a pilot tunnel drive was first undertaken in the southern tube. The breakthrough in the eastern pre-cut took place on April 15th, 2005. On account of the unfavourable geological conditions, which were discovered when driving the pilot tunnel in the southern tube, the final approx. 74 m of the northern drive were also headed in similar fashion. In spite of the difficulties, the breakthrough here took place on April 20th, 2005. The subsequent residual crown, bench and floor headings were completed at the end of June 2005. Since April 2nd, 2005, the permanent lining for the Heidkopf Tunnel is being completed in watertight concrete in keeping with the contractor's special proposal. The tunnel will be opened for traffic at the end of 2006.

 

  • Country: Germany
  • Region: Lower Saxony - Thuringia
  • Tunnel utilization: Traffic
  • Type of utilization: Road tunnel
  • Client: Federal Republic of Germany - Land of Thuringia
  • Consulting Engineer: DEGES Deutsche Einheit, Fernstraßenplanungs- und -bau GmbH, Müller & Hereth
  • Examination: Prof. Duddek und Partner GmbH
  • Contractor: Beton- und Monierbau GmbH, Stutz GmbH & Co. KG, Heinrich Rohde Tief- und Straßenbau GmbH
  • Main construction method: Trenchless
  • Type of excavation: Drill-and-blast/Excavator
  • Lining: Concrete formwork
  • No. of tubes: 2
  • Tunnel total length: 1,724 m (northern tube); 1,720 m (southern tube)
  • Cross-section: 88-105 m²
  • Contract Volume: € 48 million (roughwork); € 12 million (operational equipment)
  • Construction start/end: 34 months
  • Opening: December 2006