The drilling system
The Geonex drilling system was developed by Finnish company Geonex Oy across a period of over 20 years working in the Scandinavian geology sector with hard rock. It is suitable for any type of ground, providing extremely efficient and cost-effective drilling methods for hard rock and mixed ground. Instead of a pressed steel tube, the tube is pulled along with a hammer. Costs for the entire project work out lower than when conventional central European drilling methods are used, as it is significantly cheaper to perform the ground survey and make the foundation for the reception pit. Even if the ground composition changes within the drilling area, there is no need to change tools and it does not lead to any other problematic situations. It is easy to set project costs and time schedules as changes in the ground composition will not have any huge impacts on the time or expense of the project. Steel tubes prevent the drill hole from potentially caving in and any deadlock situations which may ensue as a result. The combination of the Geonex drilling machine, drilling system and steel tube enable drilling work to be highly accurate and can be used for most kinds of sewers, for example. There are no restrictions when it comes to drilling angles and the system makes it possible to drill “blind holes” which do not go all the way through the ground, e.g. for a HDD launcher. There are reference projects which demonstrate a drill hole being drilled over 300m into pure rock without a steel tube and using a manoeuvrable drill head. The drilling system is also suitable for vertical drilling, such as in deep foundations. Besides the actual drilling system, Geonex also offers specialised drilling machines and the corresponding powerpacks.
Example of a typical Geonex drilling machine (Type HZR610, also available in Central Europe from 2017).
The machines are not only robust, but they are also highly automated and extremely versatile in terms of settings.
Use in hard and challenging geological conditions
Microtunnel AG have a wealth of experience, enabling them to strengthen their status as drilling specialists by starting to offer the Geonex drilling system for use in hard or challenging geological conditions. Microtunnel AG can use this system to drill lengths of around 100 metres using a sheath of 139.7 to 1220mm in diameter. As Geonex Oy are making multiple drilling machines available in Central Europe this year, it will enable the same kind of projects to be organised quickly. What’s more, Microtunnel AG also offers conventional drilling methods as a matter of course, these including thrust boring (either with or without a down-the-hole hammer), pipe jacking, horizontal drilling (HDD), ramming, burstlining and microtunneling.