Speaker
Description
A 70 m long, 35 m wide and 22 m deep excavation pit was created in Basel for the construction of a new research tower block. The excavation pit is located in the inner city, in the middle of the industrial and research area of a pharmaceutical company with sensitive neighbouring buildings (adjacent to the tallest building in Switzerland at 205 m).
To protect against earth pressure and water pressure of up to 9 m in the highly permeable subsoil (gravel), only one support in the form of a spacer slab was constructed. This was done both at the request of the client, who wanted an anchor-free excavation pit, and in order to optimise the planning and ecological balance of the excavation pit. This was achieved by means of large triaxial tests on the existing gravel (Niederterrassenschotter) to determine the effective shear parameters. The results of the tests showed a significant improvement in the shear parameters, which made it possible to completely dispense with anchoring the excavation pit.