This technique is particularly suitable for large construction- or infrastructural works in rural areas.
MT-Piles (Microtunneling piles) are drilled into the ground and the drill head is recovered after placement. Van Leeuwen has developed this technique in cooperation with Strukton Betonbouw in order to replace the existing foundation supporting Amsterdam Central Station, as part of the new Noord-Zuid Metro network. Because of the non-rotating manner in which the piles are placed, these can be interlocked, allowing different ways to close up the space in between.
This method allows us to place large foundation piles up to great depth without causing potentially dangerous vibrations while requiring only a limited construction space.
This type of Vertical Micotunneling has first been applied in a large-scale project during the placement of two tubular pile retaining walls supporting the 19TH Century Amsterdam Central Station, enabling passage of the Noord-Zuid Metro line. The pipe wall supports the overlaying emplacement and served as a cofferdam wall during the excavation of the new tunnel trench. The MT-Tubular Pile Wall construction site was located at the existing passenger tunnel, with a maximum working height of 3,10 meter. The MT-Piles were therefore built up using interconnecting pipe segments, fitted with a locking system, with an approx. length of 1,85 meter.
The diversity and size of the available working area have been of great logistic consequences for the realisation of this project. The limited space has therefore been a leading factor in the very compact design and build of the MT material. For the installation of the tubular pile wall two complete drill sets have been developed and used. The long piles (up to 70m) have all been fitted with a pile point injection after being filled with concrete. The shorter piles (up to 30m) are sand filled and topside filled with armoured concrete.
For more information please read the MT-Piling Amsterdam Leaflet