Recent developments in the application of HDPE vertical barrier systems in The Netherlands

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In the last two years, several large infrastructure projects were successfully constructed in the Netherlands with the use of HDPE vertical barriers. The executed schemes used HDPE screens made of 2mm thick HDPE liner welded to patented HDPE Geolock profiles. The screens have a width of 2.5 meter and lengths ranging from 8 meter to 26 meter. During the installation, a hydrophilic swelling cord was incorporated into the locks to create a complete seal. This article describes the application of the HDPE barrier on six different projects. It includes the design aspects, installation methods as well as laboratory measurements with regards to the durability of the material used, water tightness of the system and swelling capacity of the swelling cord when used in salt water. In the projects described, the barriers were used to prevent horizontal flow of water. On the projects the screens were installed by different contractors using equipment supplied by the manufacturer of the HDPE screens. In four projects (three near the city of Leeuwarden and one at the N381), the screens were used in the construction of aqueducts and underpasses. The screens were installed with a special installation plate in narrow trenches, made using partial predrilling and displacement, as well as in ‘ mixed-in-place’ walls up to a depth of 18 meters. Near Nijmegen the screens were used in a river widening project to prevent the flow of water to the low lying land during high river discharges. The screen was installed using a reclaimable weight down to a depth of 26m in a ‘ cement-bentonite’ trench made by a diaphragm wall grab. In a project near Rotterdam the screens were also installed in a diaphragm wall. They were installed to prevent ground water inflow into a long low lying section of a new highway.