1. Department of Geotechnical Engineering, Bauhaus-Universität Weimar, Coudraystraße 11c, Weimar 99423, Germany (Corresponding author), e-mail: torsten.wichtmann@uni-weimar.de, https://orcid.org/0000-0002-9250-7014
2. Institute of Soil Mechanics and Rock Mechanics, Karlsruhe Institute of Technology, Engler-Bunte-Ring 14, Karlsruhe 76131, Germany