Abstract:The model test can quantitatively and qualitatively reflect the variation law of physical parameters based on simplified ontology. Herein, loess and sand are considered to be the aggregates, gypsum and cement are considered to be the cementing material, water is considered to be the regulator, and the orthogonal test method is used to prepare a material similar to the surrounding grade-V soft rock. The physical and mechanical parameters of the material can satisfy the requirements and appropriately simulate the surrounding grade-V soft rock of a tunnel. On this basis, the steel cylinder model test is used to observe differences with respect to the stress-varying slope, self-stabilization time, and strain of the test group under different material ratios. Further, the excavation and unloading effects of the surrounding grade-V rock are explored under a high geostress based on the variation of rock mass at the opening of the model after loading. The test results denote that different proportions of similar materials will cause variation of the physical and mechanical properties and that the elastic modulus exhibits considerable influence; furthermore, the self-stabilization time of the material increases, the stress release becomes considerably thorough, and the overall variation trend decelerates with an increase in vertical pressure.
