Demands for Seismic Site Investigation at Wind Power Station Foundation in Former Mining Areas

The application of seismic methods in geotechnical site investigation is used to determine the initial shear stiffness in soils. Specific information about the reliability and the trust regions at the determined soil profiles are necessary to use these methods in geotechnical design processes. Therefore, experiences show that higher modes in seismic surface wave fields should be considered. Due to non-unique inversion processes a trust region and a reliability of the soil profile has to be given for geotechnical design processes. The reclaimed mining areas are loose artificial landfills of sand, silt and clay with depth up to 100 m with rising ground water levels. These areas offer a large geotechnical risk for the foundation of wind power stations up to a height of 140 m. To reduce the design risk and decrease the costs a combination of conventional tests, seismic field tests and supplemental laboratory tests are proved to get the significant increase in information about the true static and dynamic soil parameters.