# Experimental Study of Material Proportioning for Similar Modeling of Brittle Rocks
## 6 Conclusions  
In this study, a brittle rock analogue was prepared using refined iron powder, barite powder, quartz sand, gypsum powder, and a rosin-alcohol solution. The rockburst tendency and brittleness indices were introduced to evaluate the material's brittleness and rockburst potential. An orthogonal experimental design and a sensitivity analysis were used to evaluate the effects of the different components on the physical and mechanical properties of the analogous materials. Based on a multiple linear regression analysis, the material-proportioning scheme was optimized. Additionally, mechanical tests were conducted to examine the failure behavior and acoustic emission characteristics of the specimens, validating the effectiveness of the proportioning scheme. The main conclusions are as follows:  
1. In the analogous material, the refined iron powder, barite powder, and quartz sand serve as aggregates; the rosin-alcohol solution acts as a binder; and the gypsum functions as a brittleness modifier. The orthogonal test results showed that the density of the specimen ranges from 2.10 to 2.40 g/cm\({}^{3}\); the compressive strength ranges from 0.12 to 1.94 MPa; the tensile strength ranges from 0.01 to 0.20 MPa; the elastic modulus ranges from 0.120 to 0.772 GPa; the rockburst tendency index ranges from 0.59 to 3.29; and the brittleness index ranges from 0.141 to 1.578. The prepared material offers a wide range of parameter variability, rapid drying, stable performance, and a straightforward manufacturing process.
2. The sensitivity analysis indicated that the refined iron powder-barite powder ratio significantly impacts the density of the analogous material, while the concentration of the rosin-alcohol solution primarily controls the material's compressive strength, tensile strength, elastic modulus, rockburst tendency index, and brittleness index. Therefore, when preparing the brittle rock analog, it is more effective to appropriately adjust the iron powder-barite powder ratio and the concentration of the rosin-alcohol solution.
3. The multiple linear regression equation effectively simulates and accurately predicts the physical and mechanical parameters of the specimen, improving the efficiency  
Figure 14: Uniaxial compression test of Jinping marble (modified from [34]): (**a**) typical stress–strain curve (AE characteristics) and (**b**) failure mode.  
of material proportion and preparation. The equation provides a scientific basis and theoretical support for the rapid formulation of rock analogs.
* An analogous material was prepared for T2b marble, and mechanical tests and acoustic emission monitoring were conducted on the specimens. Under uniaxial compression and Brazilian splitting conditions, the fracture mode and acoustic emission characteristics of the specimens were found to closely resemble those of brittle rock. This also validated the feasibility of the preparation method for rock analogs.  
Conceptualization, C.Z. and S.W.; methodology, C.Z.; software, R.P.; validation, C.Z., C.C. and S.W.; formal analysis, C.Z.; data curation, C.Z. and R.P.; writing--original draft preparation, C.Z.; writing--review and editing, S.W., C.Z., C.C., Z.X. and R.P.; visualization, C.Z. and R.P.; supervision, S.W. and C.C.; project administration, S.W.; funding acquisition, S.W. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China (51934003, 52334004, 42307233) and the Yunnan Major Scientific and Technological Projects (202202 AG050014).  
Not applicable.  
The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding authors.  
We are grateful to [PERSON] for his assistance during the experimental process.  
The authors declare no conflicts of interest.