An experimental study of the mechanical properties of the Bimrock rock mass with different cementing strength based on orthogonal tests

The mechanical properties of Bimrock under different cementation strength are rarely studied, and the cementation strength has an important influence on the mechanical properties and deformation and failure characteristics of Bimrock. In order to explore the influence of different cementation strength on the mechanical properties of Bimrock, the proportion test of Bimrock cementation matrix was conducted by using the orthogonal test design method, and the parameter sensitivity analysis was carried out on the strength mechanical parameters of the samples with different proportions of matrix. Based on the orthogonal test results, the Bimrock samples with different cementation strength were made, and the influence of different cementation strength on the mechanical properties of Bimrock was analyzed through the uniaxial compression test. The results show that the uniaxial compressive strength and elastic modulus of the Bimrock specimens are positively correlated with their cementation strength. From weak cementation to strong cementation, the peak uniaxial compressive strength increases from 11.02 MPa to 34.21 MPa, and the elastic modulus increases from 2.11 GPa to 5.57 GPa, respectively. With the increasing bonding strength, the number of surface cracks in each stage from deformation to failure decreases. The compression failure mode of the strongly bonded specimen is the through failure of a single main crack, with short failure time and obvious brittle failure. The overall and local shear failure occurred in the moderately cemented specimen, which is represented by a shear failure surface that obviously penetrates the whole specimen and a shear failure surface that only penetrates the lower part of the specimen. The weak cementation sample is subject to transverse tensile failure. A number of tensile cracks parallel to the vertical direction can be seen, and the failure characteristics of coexistence of tensile and shear failure can be seen locally. From deformation to failure, there are many cracks that are relatively broken, and the failure time is relatively long. The engineering problems of Bimrock are complex and difficult to deal with. The research on the mechanical properties and deformation and failure characteristics of Bimrock is of great significance for engineering construction and geological disaster prevention.