Experimental investigation of mechanical behavior of bedded rock salt containing inclined interlayer

Uniaxial and triaxial compression tests have been carried out on specimens of rocksalt, interlayers, and composite rock salt (containing inclined interlayers). In combination with failure mechanism analysisof the stratified rock structures, the variation and impact factors of bonding stresses between the layers have been investigated, and the fracture properties and failure mechanisms of inclined bedded rock salt have been revealed. The research demonstrated that the inclined interlayer influences the deformation and fracture properties of rocksalt. Due to the composite mechanical characteristics, cracks primarily initiate near the interface region, and then propagate to the interlayer and the rock salt adjacent to it. The thickness of the interlayer affects the entire performance of the composite specimen and governs the development of the local fractures. Macro-cracks tend to form more easily in the test specimens that contain a medium-thick interlayer than in the ones containing only a thin interlayer. Increasing confining pressure gradually changes the overall mechanical behaviors from brittle to more ductile at higher confining pressure. The ductile behavior is characterized by differences of strain-hardening behaviors and also the geometry of cracks at different locations in the interlayer as compared to the results of uniaxial compression tests. (C) 2014 Elsevier Ltd. All rights reserved.