How can the liquefaction resistance for open-cast mine dump soils under irregular, earthquake-typical excitation be determined?

This is usually done by determining the stress ratio CSR on the basis of the surface acceleration. It is unclear how the factor for converting the irregular signal into a regular one should be selected.

In collaboration with Lukas Knittel (KELLER), Paul Raabe and Dieter Dahmen (RWE), Torsten Wichtmann (Ruhr University Bochum), Sabine Gehring and Hans Henning Stutz (Karlsruhe Institute of Technology (KIT)), we have investigated the liquefaction behaviour of an opencast mine tipping floor when subjected to an earthquake signal using triaxial and hollow cylinder triaxial tests (see Figure 1) under both regular and irregular cyclic loading. The earthquake signal typical for open-cast mining was determined by means of a coupled dynamic finite element calculation. It was shown that the factor β for converting irregular signals into regular signals depends on the type of loading and the magnitude of the static shear or deviator stress. Based on these investigations, recommendations for the approach of β for the Rhenish mining area are given.

Further details can be found in our full paper in the geotechnik