SIMILAR MATERIALS FOR QUASI-STATIC SCALED TESTS OF FAULT-CROSSING TUNNELS

The design of similar materials is one of the key links to ensure the matching of the physic-mechanical properties between the prototype and the test specimens. Based on the prototype of the Xianglu mountain tunnel of the water diversion project in the central Yunnan province, China, the scaling relationship of the physical quantities in the quasi-static scaled test of a fault-crossing tunnel is derived in this study according to the similarity theory and dimensional analyses. The similar materials of concrete and rock mass used in the test are developed with barite powder and sand as the aggregates and with gypsum and lime as the cementing material. The effects of each component on the physic-mechanical properties of the similar materials are investigated through orthogonal tests. The test results indicate that the strength, elasticity modulus and density of the similar materials can be significantly changed by the overall content of the high-strength gypsum and water-gypsum ratio. Small variation of the strength of the similar material is found when the sand-gypsum ratio is between 0.8 and 1.2, but the strength significantly decreases when the sand-gypsum ratio is between 3 and 12. The elastoplastic performance and the brittle failure mode of Grade C30 concrete can be well simulated by the similar material made of high strength gypsum, low strength gypsum, barite powder and sand. The tensile splitting and the diagonal shear failure modes of rock mass of Grade IV and V can be well simulated by the proposed similar material made of high strength gypsum, lime and sand. The development process and ratios of similar materials can provide important reference for model test and numerical simulation.