Stuttgart–Ulm Rail Project: Imberg Tunnel

Quelle/credit: DB Projekt Stuttgart–Ulm

Overview of PFA 2.3 Alb Plateau

Quelle/credit: DB Projekt Stuttgart–Ulm

General plan of the Imberg Tunnel

Quelle/credit: DB Projekt Stuttgart–Ulm

Imberg Tunnel cross-sections: cut-and-cover section (left) and conventional tunnelling section (right)

Quelle/credit: DB Projekt Stuttgart–Ulm

Geological longitudinal section

Quelle/credit: DB Projekt Stuttgart–Ulm

Excavation work on the precut South (July 2015)

Quelle/credit: DB Projekt Stuttgart–Ulm

Crown face in the stratified (on the left) and massive facies (on the right) of the White Jura

Quelle/credit: DB Projekt Stuttgart–Ulm

Karst scenarios in keeping with the design planning and construction contract

Quelle/credit: DB Projekt Stuttgart–Ulm

Karst exploration accompanying driving

Quelle/credit: DB Projekt Stuttgart–Ulm

Open karst structure in the tunnel (left); backfilling a karst hole (right)

Quelle/credit: DB Projekt Stuttgart–Ulm

Seismic investigation of the crown invert

Quelle/credit: DB Projekt Stuttgart–Ulm

Anomaly map for the crown invert

Quelle/credit: DB Projekt Stuttgart–Ulm

Seismic ground investigation in the precut South

Quelle/credit: DB Projekt Stuttgart–Ulm

Installing the tunnel drainage beneath the inner shell at the side

Quelle/credit: DB Projekt Stuttgart–Ulm

Concreting the invert

Quelle/credit: DB Projekt Stuttgart–Ulm

Assembling the vault formwork carriage: Forced break on account of the elements

Quelle/credit: DB Projekt Stuttgart–Ulm

Reinforcement for the inner shell

Quelle/credit: DB Projekt Stuttgart–Ulm

Start of the cut-and-cover construction section South

Quelle/credit: DB Projekt Stuttgart–Ulm

Closing the gap between cut-and-cover and mined construction sections

Quelle/credit: DB Projekt Stuttgart–Ulm

The Imberg Tunnel is located on the Swabian Alb plateau, which is crossed by the new Wendlingen–Ulm rail link. This journal has already reported on this major project and the plan approval section PFA 2.3 Alb Plateau [1]. The Imberg Tunnel is 499 m long, which means it is numbered among the shortest for the Stuttgart–Ulm rail project. The ICE will only need roughly 7 seconds to pass through the tunnel.

The position of the tunnel in the second contract section of the around 23 km long plan approval section can be seen in Fig. 1. Topographical marginal conditions define the length of the 220 m central construction section, which is driven by conventional means. Cut-and-cover sections extend the tunnel at both sides (Fig. 2). On the south side this is defined by the planned or rebuilt road network; at the north side a highly frequented game pass that crosses the track has to be catered for. Subsequently the latter will be continued in the form of a wildlife bridge over the A8 motorway.

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