Dreidimensionale Berechnungsmodelle zur Bemessung einer ovalen, tiefen Baugrube bei schwierigen geotechnischen Randbedingungen

3D calculation models for the design of an oval, deep excavation pit under difficult geotechnical circumstances.

In the course of the expansion of the existing Rheinkraftwerk Iffezheim (i.e. running-water power station in Iffezheim), a companionship of the EnBW Kraftwerke AG and EDF Electricité de France, three excavation pits are required to install the fifth bulb turbine: the uptstream excavation pit (entry), the main excavation pit (power plant) and the downstream excavation pit (siphon pipe and exit). All three excavation pits are in the middle of an artificial island which is connected to the existing power plant. The main excavation (dimensions 51 m to 36 m, excavation depth appr. 34 m) is an oval (ellipsoidal) excavation pit without struts and rear anchorage of the pit walls. Because of the shape of the main excavation pit and the asymmetric geometric and load boundary conditions, a complex three-dimensional numeric model for the calculations was needed which was able to take into account the special structural behavior of the excavation pit appropriately.