In the city of Groningen, the Southern Ring Road is being reconstructed within the greater project ‘Aanpak Ring Zuid’ (Southern Ring Road Project).
Where at present traffic lights are in place at the most important road traffic junction in the city, in future the traffic will be able to flow without obstruction using feed and exit slip-roads and flyovers. One section of the Southern Ring Road Project is a tunnel, approximately 1.3 km long, within which the ring road will be displaced from the current surface construction 10 m above NAP* to the new underground position at about 8 m below NAP.
GEO2 Engineering B.V. is responsible for the geotechnical design for implementation (DI). We have been commissioned to do this by Vienna Consulting Engineers ZT GmbH in close collaboration with the construction firm Combinatie Herepoort (CHP).
Geotechnical ‘specials’ within the DI are the sheet pile walls with a retaining height of approximately 18 m, immediately behind which the traffic on the southern ring road will ride along a temporary by-pass, at the same time as building excavation for the future sub-surface traffic tunnel is being constructed. In addition there are various buildings adjacent to the construction site for which strict limits on deformation apply.
The deformation of the adjacent buildings are determined using Plaxis 2D. Based on the calculated rotation and elongation of the buildings, we determine under which class of damage (following Boscardin and Cording) these buildings occur. In this way, account is taken of various causes of damage, including the settling of sand layers caused by vibration, the bending deformation of the sheet piling walls in the exposed situation and, where relevant, the effects of vibrations on the sheet piling walls.
For more information please see the website: https://www.aanpakringzuid.nl
*NAP = Normaal Amsterdams Peil, Amsterdam Ordnance Datum, a vertical reference datum widely used in Western Europe.