Strukton Infratechnieken plays a leading role in the development of microtunnelling. This method is often used in urban environments, where there is no room for open trenches or large circular cofferdams.
The principle of microtunnelling can be described as using hydraulic jacks that push prefabricated tunnel units through a hole drilled in advance using a tunnelling drill. We developed an entirely new type microtunnelling technique for the construction of Amsterdam’s North/South line: vertical microtunnelling. The old foundations under the platforms of Amsterdam’s Central Station needed to be replaced so that a new metro station could be built underneath. A table structure with two tubular pile walls was chosen for the realisation of these activities. For technical reasons, the microtunnelling technique was also chosen. Because the working height under the platforms was only 3.1 metres, units with a height of 1850 mm were used.
The advantages of vertical microtunnelling are self-evident, as drilling can be performed in locations with a minimal working height. Furthermore, the considerable inconvenience and costly collateral damage caused by conventional piledriving and vibration techniques are avoided. Thanks to this new drilling method, building activities can be performed under existing multi-storey car parks, for example.