Foundation of wind power station on mining dump applying deep soil compaction

The wind power station Klettwitz in Germany was constructed on a 90 m thick mining dump. To enhance the foundation performance regarding bearing capacity and deformation behavior, a special soil improvement system applying a combined system of vibro-floatation and vibro-displacement was developed and implemented. With this system the tower of the wind power turbine can be founded on shallow footing fulfilling both the ultimate limit and the serviceability limit requirements. Numerical analyses were carried out during the design stage to study the performance of the foundation and to prove the design criteria. The results of the numerical analyses, the in-situ tests such as CPT, which were executed before and after conducting the soil improvement measures, as well as the settlement measurements will be presented and discussed. The results demonstrate the efficiency of this combined soil improvement system to enhance the performance of sensitive structures on inhomogeneous, subsidence-prone mining dumps.