Overburden drilling with a KEMM KR 805-3G to reinforce Westerland’s seawall

More than a hundred years ago, the seawall in Westerland on the island of Sylt was built to protect the town’s exposed houses against tidal waves from the sea. With masonry breaking off in places and damage to some of the joints, the 500 meter long beach front wall is currently being reinforced section by section. This is achieved by erecting 2.2 meter wide, 4.4 meter high, pre-cast, 13 ton, reinforced concrete elements, directly in front of the old seawall. Each element is held in place by two 18 meter deep tie backs, drilled at angles into the ground acting like giant dowels.

Our Hamburg based customer, Neidhardt Grundbau GmbH, installed the tie backs on two sections of the wall using the overburden method. A KLEMM KR 805-3G rig with flushing head was used to install 130 GEWI grouted 40 / 50 DKS piles, with a total drilling length of 2,188 running meters.

The reinforcement of the entire seawall is expected to cost around 10 million EURO with an estimated completion date in 2023, therefore protecting Westerland and its people against future tidal waves.