In the Principality of Liechtenstein, a special civil engineering project of this kind has now been realized for the first time - a first in the heart of Europe.

 

The dike is located at the river Rhine in Schaan the largest municipality of Liechtenstein by population, where the river forms a natural border with Switzerland.

BAUER was awarded the execution of a cut-off wall at the existing dike. The cut-off wall has permanent purposes and serves to ensure safety behind the dike.

The aim was to strengthen the existing dike to minimize possible seepage. Therefore, embedment of the cut-off wall in the flood deposits up to approx. 50 cm above the groundwater-bearing Rhine gravel layer was required.

The cut-off wall was installed to a maximum depth of 10.00 m.

 

Drilling works were executed by means of the Mixed-in-Place construction method with a BAUER RG 16.

 

• Employer: Amt für Bevölkerungsschutz, Liechtenstein
• Client: Büchel Spezialtiefbau
• Execution: BAUER Spezialtiefbau Schweiz AG

 

 

 

Location

The site of the dike is located along the river Rhine to the west of the village of Schaan approximately 2 km north of the national capital Vaduz, Liechtenstein.

 

Scope of work

• Mixed-in-Place cut-off wall
• In total:             5,200 m²
• Nominal thickness: 37 cm
• depth: 10 m

 

Geological conditions

The soil in the cut-off axis consists of fill material (coarse- and fine-grained, sandy, silty), followed by deposits due to flooding and sedimentation of the Schaan valley plain. The subsoil below consists of Rhine gravel (gravel and sand).

 

 

Miscellaneous

Since the project was implemented in a water protection area and in the immediate vicinity of a water pumping station, the underlying Rhine gravel had to be retained as a water-bearing layer. In the process, the depth of the wall was determined in advance by consulting engineers to prevent the cut-off wall and slurry used from penetrating into the water-bearing Rhine gravel.

To protect the meadow on the dike – both on the land side and on the Rhine side – it was covered with geotextiles.

 

Equipment

• BAUER RG 16
• Mixing plant

 

Construction period

March 2022