Excavation building site in primary embankment: twin piling wall combined with underwater concrete
A completely underground extension of Strandhotel Cadzand-Bad will be realized in Cadzand-Bad. The project is located on the North Sea coast in the primary flood defense that exists there. The sub-structure, consisting of 3 complete layers, is realized in a completely closed construction pit. The extension is in the hands of Aannemersbedrijf Van der Poel bv (main contractor) and Funderingstechnieken Verstraeten bv (subcontractor foundation works and construction pit). The design of the construction site including the reinforced underwater concrete was realized by BMNED from Terneuzen.
For the foundation design was opted for Fundex grout injection piles combined with Fundex anchors. For the design of the horizontal defenses, a Twin Pole wall was chosen. The foundation piles, anchors blocks and pile wall have been realized using two drilling rigs. The first pile was placed in autumn 2015. The last pile was installed in mid-April 2016.
For the design of the vertical seal was opted for a reinforced underwater concrete. The vertical balance of the construction pit could be guaranteed up to level 2 m1 -NAP without additional measures. After the entire construction pit was excavated to level 2 m1 -NAP, the construction pit was filled with water and started with the hydraulic excavation to 5 m1 -NAP. Local has been excavated to approximately 6.5 m1 -NAP.
A total of approximately 4,000 m3 of steel fiber-reinforced underwater concrete was dumped during a period of approximately 49 hours, resulting in an average bulk volume of approximately 81.6 m3 / hour. In view of the composition of the mixture, in particular the presence of the steel fibers, it can be stated that a very high average pour volume has been realized here.
Based on the data from various maturity meters that were included in the underwater concrete, 18 days after the underwater concrete was installed, the pumping of the construction pit was started, resulting in a closed construction pit.
Omroep Zeeland has made a video of the activities at the time of applying the underwater concrete. Mr. De Nijs speaks about this and gives a further explanation about the use of underwater concrete.
Facts & Figures
- Van der Poel