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.
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
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
Construction period
March 2022