The Oder dykes in the Uckermark showed numerous breaches as a result of flood events. An existing dyke had to be reconstructed. With Secugrid® HS high strength geogrids, safe life in the dyke area is possible again.
In the summer of 1997, the largest known flood occurred along the German-Polish border river Oder. The flood situation lasted several weeks. The water flooded around 5,500 hectares of agricultural land and residential area with about 400 houses as a result of multiple dyke failures. Several thousand people had to be evacuated.
After this flood in 1997 and subsequent smaller flood events, the dykes suffered several damages. These were caused by weak points in the dyke geometry and problems in the foundation soil.
To withstand future flood events, an existing dyke was reconstructed over a length of 3km. Soil investigations below the old dyke revealed relatively deep soft layers of peat, organic silt and clay.
To ensure sufficient stability of the new dyke, the geogrid Secugrid® HS was installed as basal reinforcement.
Secugrid® HS geogrids are laid geogrids made of high tenacity polyester filaments with an extruded polyethylene protective coating and welded junctions. Secugrid® HS combines high tensile strengths and low creep tendency with extreme robustness and resistance.
The individual geogrid panels were installed with their main stress direction perpendicular to the dyke axis by using a spreader bar. Adjacent panels were overlapped by 50cm transverse to the direction of installation.
Over the entire length of the dyke a total of approx. 63,000m² of the high strength geogrid was installed.
The old dyke was partially removed and reconstructed as a so-called “3-zone dyke”. On the slope, facing the water-side, a geosynthetic clay liner (GTD) was installed as a sealing system.
Due to its high robustness and long-term tensile strength, Secugrid® HS contributes substantially to the flood control measures along the German-Polish border.