Ostsee LNG Pipeline – Trenchless Shore Crossing

Challenging microtunnelling beneath the Baltic Coast

Wind, waves and rock formations set the scene for this demanding tunnelling project. Between Mukran and Lubmin, STRABAG is constructing a 1,1-kilometre-long Liquid Natural Gas (LNG) underwater supply pipeline crossing the shoreline. Hidden beneath the seabed once completed, the pipeline requires highly precise tunnelling under constantly changing weather and sea conditions.

The DN 2000 pipeline is being installed beneath the Baltic Sea using a microtunnelling method through hard rock. Targeted underwater excavation of the seabed provide the conditions required for the offshore recovery of the tunnel boring machine (TBM) by the client. A crane mounted on a barge and a team of professional specialist divers are deployed for these operations.

From site preparation and the construction of the entry pit to the tunnel drive itself and the final grouting of both the tunnel and the annular space between the gas pipeline and the concrete pipe, every construction step is carefully coordinated and interconnected. 

Scope of Work

• Site preparation and setup 
• Construction of the launch shaft 
• Execution of the 1,1 km microtunnel drive 
• Mobilisation and demobilisation of the winch 
• Grouting of the tunnel and pipeline annulus