Construction of a bitumen-reinforced dyke in northern Germany
In April 2015, after 2 years of construction efforts, the teams at Eurovia Hamburg delivered the company’s most northernly project in Germany: on the island of Sylt in the North Sea. They built a 2.5-km dyke using a special construction method.
In efforts not to impinge on protected natural habitats on either side of the dyke, the slope of the embankment had to be adjusted, thereby making it impossible to apply the standard stabilization method of using enriched sea clay. Consequently, the embankments were covered with bitumen-bound gravel over a layer of uncompacted filter sand. At high tide, the force of the waves is mitigated by this rough coating. The coating is sufficiently porous to allow the dyke’s internal pressure to escape, thereby protecting the structure from erosion.
In all, 120,000 m3 of earthworks was required on the island of Sylt, 36,000 pinewood pillars were planted to stabilize the base of the dyke, and 28,000 tonnes of the gravel-bitumen mix were implemented.