## 4 Conclusions  
In this study, 11 groups of rock-like specimens with different proportions were prepared by using cement, quartz sand, and gypsum as raw materials. The failure experiment and acoustic emission experiment of rock-like specimens under uniaxial compression were carried out. The following conclusions can be drawn:  
1. The rock-like specimens made of quartz sand, cement, and gypsum can simulate the rock mass in actual engineering, and the mechanical properties and failure process of the two have high similarity.
2. When the material is made of quartz sand-cement, the strength of rock-like specimens is positively correlated with the proportion of cement, the brittleness of the material is obvious, and it can simulate hard rock materials. When gypsum is added, the  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Specimen Number**} & \multirow{2}{*}{**Mass Proportions**} & \multicolumn{4}{c}{**The Change of Cumulative Ringing Count in Each Stage**} \\ \cline{3-6}  & & **I** & **II** & **III** & **IV** \\ \hline A1 & 1:0.8 & 0–7.5\% & 7.5–28.3\% & 28.3–55.4\% & 55.4–100\% \\ A2 & 1:1.2 & 0–4.8\% & 4.8–23.3\% & 23.3–64.8\% & 64.8–10  
strength of the rock-like material significantly decreases, exhibiting a strong negative correlation with the proportion of gypsum.
3. The rock-like specimens made of quartz sand and cement show splitting failure characteristics after uniaxial compression, and the surface cracks of the specimens are less. When gypsum is added to the rock-like specimen, shear failure is the main failure after uniaxial compression, and there are many secondary cracks between the primary cracks on the specimen surface.
4. The maximum value of the acoustic emission ringing count is positively correlated with cement content and negatively correlated with gypsum content. The change in acoustic emission cumulative counts roughly goes through four stages, which have a good correspondence with the initial compaction stage, elastic stage, damage stage, and post-failure stage of typical rock uniaxial compression failure.  
Limited by the test cycle, only 11 groups of rock-like specimens with different ratios were studied in this study. In the future, the experimental scheme should be finely divided. Different binders have different effects on the physical and mechanical properties of rock-like materials. In this paper, only water was selected as the binder of materials. At the same time, the amount of water used in the experiment was fixed, and the influence of the amount of water on the physical and mechanical properties of rock-like materials was not studied in this paper. In the next study, the effects of the type and amount of binder on the physical and mechanical properties of rock-like specimens will be studied.  
Validation, S.D. and Q.S.; formal analysis, Q.S.; investigation, R.H.; resources, S.D.; data curation, Q.S. and Y.X.; writing--original draft preparation, Q.S.; writing--review and editing, Q.S. All authors have read and agreed to the published version of the manuscript.  
This study was financially supported by the Key Project of National Natural Science Foundation of China (No. U183920051), the Innovative Talents of Colleges and Universities in Liaoning Province (No. LR2019031), and the Basic Project of Education Department of Liaoning Province (No. LJ2019L006).  
Not applicable.  
The data used to support the findings of this study are available from the corresponding author upon request.  
The authors thank the anonymous reviewers for their critical remarks and comments, which greatly helped to improve the manuscript.  
The authors declare that they have no conflicts of interest regarding the publication of this paper.