Through underground sealing systems direct influx of brine or water in disposal cavities of underground waste repositories is initially ruled out. Therefore dam materials with restraint systems, in case of a water or brine intrusion, are a good choice. To simulate the behaviour of such a material with a chemical based restraint system, CHM coupling is essential. This paper deals with a numerical model which describes the coupled C: HM behaviour of a self healing salt based backfill “SVV”. Therefore with implemented thermodynamic equilibrium calculations the phase composition and solid phase integral volume can be predicted and thus the curing process during the injection of solution described. Concurrent samples of SVV have been produced and thereby measured data has been compared to the results of simulations. Afterwards the samples were disassembled and investigated with respect to their mechanical behaviour and composition in terms of mineral phases for further comparisons between simulation and experiment.