ABSTRACT
The experimental data basis for the adjustment of the constitutive model for the reference backfill was extended regarding higher initial porosities (37–38%) and permanent deviatoric conditions. The parameter set of the constitutive model was modified with respect to the effect of initial porosity. The experimental technique of the true triaxial testing device was verified within a benchmark exercise and with the aid of special tests concerning wall friction and anisotropy of the testing material. The results from the TSDE (formerly TSS) in-situ test in the Asse salt mine were evaluated for a first validation of the constitutive model developed for the reference backfill material. It was found that in the in-situ test the reference backfill behaves significantly more stiffly than predicted by the constitutive model adjusted to the laboratory test results. It is presumed that this discrepancy is mostly due to some demixing of the crushed salt during the slinger backfilling procedure.
