New Ebensfeld-Erfurt Line Augustaburg Tunnel

The German Unity No. 8 transport project relates to the route in a south-north direction linking Nuremberg, Erfurt, Leipzig/Halle and Berlin. The VDE No.8.1 part-section is the Ebensfeld-Erfurt connection, which links construction section 3240/3250 of the new line coming from the south with the upgraded route leading to the Erfurt hub. The work to be performed in this section involves the construction of the 1,404 m long, twin-track Augustaburg Tunnel including emergency exit, shaft building, rescue zones at the portals and linking the rescue zone accesses to the public road network. The Augustaburg Tunnel is located on the south-western fringe of the Thuringian Basin, which is characterised by shallow-bedded Mesozoic sedimentary rocks such as keuper, shell limestone and mottled sandstone. The mined part of the tunnel passes through Upper Shell limestone with its clay, marl and limestones, which are settlement-prone. The ground is classified as highly to extremely highly fissured. The free groundwater level is located at up to 10 m above the tunnel roof. An excavator was employed for the mined section using the NATM with double-shell-lining. The tunnel was tackled from the northern cutting in part-sections- crown, bench and floor. The overburden amounts to at least 11 m with a maximum of 22 m. The tunnel was produced as a pressure-tight tube with continuously laid waterproofing plastic membrane. The maximum block lengths for the permanent lining in the running tunnel amount to 12.50 m whilst in the portal areas the block lengths are 6.25 m. The portals were produced in watertight concrete. Current fire and catastrophe protection requirements were taken into account when the Augustaburg Tunnel was planned. The rescue gallery (19 m long), whose access is equipped with locks and storage space, is located 411 m from the south tunnel portal. On the surface, an emergency exit building with a two-winged escape door and safety lock is to be set up. The rescue zones at the north and south portals and the emergency exit building are to be fitted with extinguishing water Containers with 100 m³ capacity. In the pre-cuts, fossil snails (ceratites) were found in the limestone marl whilst the remains of a large mammal (horse) were recovered from an earth slip zone. Driving operations commenced in October 2003. Initially it proved difficult to penetrate the upper shell Limestone with its clay, marl and shell-limestone layers given active fracture tectonics and the presence of underground water. After some 120 m, it was possible to separate the crown drive from the follow- up bench/floor Operations on the basis of geotechnical assessments and to tackle it in advance. The crown was broken through in the south in August 2004. Work started on the permanent lining for the running tunnel from the north in January 2005. Parallel to the concreting of the running tunnel (floor and vault), the emergency exit was tackled. The permanent lining together with the portal structures were scheduled to be finished in August 2005.

Country: Germany
Region: Thuringia
Tunnel utilization: Traffic
Type of utilization: Main-line rail
Client: Deutsche Bahn AG, represented by DB ProjektBau GmbH, NL Südost, PZ Erfurt
Contractor: Hochtief Construction AG, Hermann Kirchner Bauunternehmung GmbH, Alpine Bau AG
Main construction method: Trenchless
Type of excavation: Excavator
Lining: Concrete formwork
No. of tubes: 1
Tunnel total length: 1,404 m, by mining means: 1,364 m by cut-and-cover: 40 m
Cross-section: excavation approx. 160 m², operation 92 m²
Contract Volume: approx. € 20.7 million
Construction start/end: October 2003 to October 2005
Opening: 2015