Basic studies of salt heaps with grain diameters of up to 65 mm, depending on the storage density and stress level

The present R and D project served, on the one hand, for strength tests by means of 15 appropriate triaxial large-scale experiments with backfull of salt fines, that means determination of materials parameters not influenced by scale effects. On the other hand, data were to be prepared for a comparison of results from large-scale and small-scale experiments. Those 15 experiments were grouped into three series wich differed by the size of the biggest grain diameter. The test material of the three series had qualitatively equal grain distribution lines displaced against each other. That made possible the determination of the material parameters K, V, E modules, Poisson ratio, angle of friction, and cohesion. In addition, a comparison of the results of the three series could show whether the material behaviour depended on the maximum grain diameter. Microscopic studies of stressed heap were designed to provide information on the behaviour of salt fines at grain limits. (orig.)