Is it possible to build wind farms on former opencast mining sites sooner than has been the case up to now? Are freshly recultivated areas already stable enough? Ruhr University Bochum, engineering office Jörss-Blunck-Ordemann (JBO) and RWE are investigating this in a joint research project.
Soils that are still young usually need to settle for several years before they can be cultivated. Modern wind turbines weigh up to 6,500 tonnes. Therefore, recultivated areas are usually only built on after up to 15 years.
On the initiative of RWE, the experts will now be investigating an operating area at the Inden opencast mine for three years. There, they want to select the most complex possible subsoil for the research project. Then the field test is due to begin with gravel and sand to be piled up on a circular area with the radius of a wind turbine. The earth masses weigh as much as a wind turbine including its foundation. Measuring devices in the soil will subsequently record any geomechanical changes. Computer calculations based on data from the field tests and accompanying geotechnical laboratory investigations will be carried out. They will not just model the settlement of the subsoil under the dead weight of the wind turbine, but also the effect of wind loads on the ground around such a turbine.
