Numerical simulations of the long-term load-bearing behaviour of abandoned sealed caverns in rock salt are very complex, especially if the cavities are back-filled with hazardous waste, and this waste has been preconditioned to a slurry suitable for wet-in-wet emplacement technology. With respect to safety analysis, it is necessary to have adequate approaches for physically modelling the mechanical processes occurring in the surrounding salt rock mass, as well as for physically modelling the mechanical-hydraulic coupled processes occurring within the sealed cavern, as well as in the surrounding salt rock mass due to the nonexcludable infiltration of pore fluids from the waste. The Lux/Wolters constitutive model was developed not only specially for this question, but also for other purposes at Chair in Waste Disposal and Geomechanics of Clausthal University of Technology. This model is based on intensive laboratory investigations and can be used for modelling the creep behaviour of salt induced by deviatoric stresses, and the thermomechanically induced damage and damage reduction processes possibly occurring in a rock salt mass, as well as for modelling changes in permeability resulting from thermomechanically or hydraulically induced damage or damage reduction processes. This paper presents the Lux/Wolters constitutive model and analyses the long-term load-bearing behaviour of abandoned waste-filled caverns after sealing, especially with respect to demonstrating the long-term safety of this kind of repository.