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Connect first, cut through later

In the near future, all ships will be sailing to and from the new ports of Maasvlakte 2 via the Yangtzehaven. That is why the Yangtzehaven will be cut through. In preparation for this project, which takes place in 2012, the Port Authority has already realised a project that is unique in technical terms.

The companies on the northern side of the existing Maasvlakte are supplied with gas and electricity, among other things, by cables and pipelines. The cutting through of the Yangtzehaven, to make Maasvlakte 2 accessible for shipping, demands a solution for these cables and pipelines.

That is why tunnels were drilled under the wide Yangtzehaven, over a length of 1,200 m. A total of six tubes with a diameter of up to one metre were installed as conduits for gas, electricity, drinking water, fibreglass and a pressure sewer. The tubes lie at a depth of 42 m and pass under the quay walls. The construction involved making horizontally guided borings. First the contractor made a pilot boring - a relatively small hole that was filled with bentonite, a thick, claylike fluid - to prevent the tunnel from caving in. The hole was subsequently enlarged a number of times until the desired diameter had been reached. After this, a tube was pulled through the tunnel in one go.

This way, the companies located on the Yangtzehaven will remain connected to the required utilities when the 600-m wide fairway is cut through in 2012. The borings were started well in advance. This is because Gasunie pipelines have a delivery time of one to one-and-a-half years. If one of the borings had failed, this would have resulted in enormous delays. The project went according to schedule and could consequently be rounded off in 2009.