## 5 Conclusions  
Aiming at the problem of the confined compaction deformation of crushed gangue, this paper studied the relationship between the compaction deformation of crushed gangue and the axial stress, water content, and relative crushing rate under different water conditions through confined compaction tests. The main conclusions are as follows:  
1. With the continuous increase in the axial stress, the axial strain of the crushed gangue samples under different water content conditions generally shows a continuous increasing trend, and the curve growth rate gradually decreases. The confined compaction deformation process of crushed gangue can be divided into three stages: the rapid compaction stage, crushing compaction stage, and stable compaction stage. The strain-stress curve will exhibit a serrated shape change at the boundary between the rapid densification stage and the crushing compaction stage.
2. According to the results of the confined compaction test of crushed gangue, the form of the fitting equation of the strain-stress curve of the confined compaction is modified and improved. Different function forms were used to fit the strain-stress curve for each of the three stages of the confined compaction deformation process. The multi-parameter logarithmic function was still used to fit the strain-stress curve in the rapid densification stage and the crushing compaction stage, while the Chapman-Richards function was used to fit the strain-stress curve in the stable compaction stage. The R-squared of the fitting results were all above 0.99.
3. The compression modulus of crushed gangue shows a good linear relationship with the water content. The maximum variation in the compression modulus under different water content conditions ranges from 9.9 to 19.3 MPa, and the greater the axial stress, the more obvious the effect of the water content on the compression modulus. When the water content is 1.5% and 3.0%, the variation rate of the rebound modulus under the axial stress of 4-8 MPa is relatively large, while in other cases the rebound modulus shows a basic linear relationship with the axial stress.
4. There is a good correlation between particle crushing and compaction deformation. The relative crushing rate increases continuously with the increase in the axial strain, and the increase rate of the relative crushing rate also increases gradually. The variation law of the relative crushing rate and axial strain is different in dry conditions and water-containing conditions. When the axial strain is the same, the relative crushing rate in the dry conditions is greater than that in the water-containing conditions.  
Conceptualization, P.L. and Y.Y.; methodology, P.L.; validation, P.L., J.L. and Y.S.; formal analysis, Y.Y.; data curation, P.L.; writing--original draft preparation, C.X.; writing--review and editing, Y.S. 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, grant number 52104088, and also by the Foundation of Liaoning province Department of Education, grant number IJKZ0361.  
Not applicable.  
The authors declare no conflict of interest.