Proportioning experiment of similar material for coal and rock model test

The similarity model test is one of the important means to study the law of hydraulic fracture propagation in coal and rock mass, the efficiency of test result depends on the selection and ratio of similar materials. In order to conduct hydraulic fracturing simulation experiment, according to the mechanical properties of raw coal, a proportioning test of similar materials was carried out by means of orthogonal designed method and a suitable similar material model for hydraulic fracturing experiment was developed. Cement and gypsum were selected as binder, coal powder was applied to the aggregate through comparative analysis. The uniaxial compressive strength, elastic modulus, Poisson's ratio and consistent coefficient of similar materials were determined through a series of laboratory tests. The mechanical properties of raw coal and similar materials were analyzed and the effect of different ratios on the mechanical properties of similar materials was studied systematically. The results showed that the mechanical properties of similar materials can meet the requirements of similar model test of coal and rock. The results of the study can provide reference for the selection of similar materials in hydraulic fracturing simulation experiment.