Abstract:
Due to the worldwide population growth, the development of sustainable infrastructure and the exploration of renewable energies plays a key role. In order to develop and expand traffic, supply and disposal networks, tunnels and foundation structures are required, with a trend towards greater depths to avoid already existing underground infrastructure.
The increasing need for complex building structures involve the development of innovative deep foundation technologies. Conventional methods like bore piles reach their technical and economic limits under certain conditions. As an alternative, new mechanized technologies, mainly coming from the tunnelling industry, have been developed to overcome challenging mixed ground conditions, high groundwater tables or economic limits in greater depths. For almost twenty years, the mechanized Shaft Sinking technology (VSM) has been in operation to build foundation and shaft structures all over the world used for tunnel projects or for intelligent underground parking systems. More than 100 circular shafts have been built with reinforced concrete lining, mainly through difficult, groundwater bearing soil, in depths of up to 115 meters. The VSM is completely remote-controlled from the surface and covers a diameter range from 4.5 to 18 meters.
Offshore foundations, especially in non-drivable ground conditions and medium water depths require drilled installation methods. The Offshore Foundation Drilling (OFD) technology, based on the concept on a full-face tunnelling machine, enables a rapid and economically drilled installation of offshore foundations in variable ground conditions and rock strengths. In 2022, drilling works for the subsea installation of 73 monopile foundations have been completed with OFD for the St. Nazaire wind farm in France. With a drilling diameter of 7.7 m, this OFD equipment is currently the largest offshore drilling rig.
This presentation will present the mechanized technologies of VSM and OFD with their application fields and benefits to the construction industry.