# The Preparation of Active Support-Based Sealing Material and Sealing Effect Analysis
## 5 Conclusions  
1. Based on the active support sealing concept of the gas drainage borehole, orthogonal tests were conducted to explore the mix ratio design of the sealing materials. On this basis, this study revealed the effects of the water/cement ratio, quicklime content, fly ash content, accelerating agent content and expanding agent content on the bleeding rate, fluidity, initial setting time, compressive strength and expansion rate of the sealing material. Through comprehensive analysis, the optimal combination of each factor is as follows: water/cement ratio: 0.9:1, quicklime content: 0.2, fly ash content: 0.3, accelerating agent content: 0.15, and expanding agent content: 0.2.
2. The properties of the sealing materials vary significantly with the confining pressure. At a higher confining pressure, the material exhibits viscous material characteristics. Under the same confining pressure condition, the higher the expansion rate is, the smaller the annular strain is. The higher the expansion rate is, the smaller the internal friction angle and cohesion are, which is reflected by the sharp decline in the peak strength of the sealing material. The active support force of the sealing material has a significant time effect. It increases rapidly at first, and then its growth rate slows down and tends towards a certain value. The maximum active support force that the material with an expansion rate of 5% can provide reaches 2.63 MPa, and that of 3% and 1% reaches 2.1 MPa and 1.4 MPa, respectively.
3. According to the active supporting force theory of sealing materials, with the increase in the active support force provided by the sealing material, the radius of the plastic zone and breakage zone decreases accordingly; the displacement around the borehole also displays a similar changing trend. This indicates that the active support force of the sealed borehole can effectively inhibit the development of cracks around the hole and reduce the generation of a gas leakage channel. At the same time, the mechanical properties of the borehole rock also have a great influence on the development of a borehole fissure. Under the action of the same burial depth and active support force, the larger the mechanical parameters of the rock are, the smaller the radius of the plastic zone and the breakage zone, and the smaller the displacement around the borehole.
4. By analyzing the on-site gas drainage concentration and negative pressure, the bag-type borehole sealing technology featured with \"two plugging and two injections\" are more effective than the traditional sealing technology used in mining. When the drainage lasts for 90 days, the gas drainage concentration with the bag-type borehole sealing device is 47.5%, increasing by 84.8%. Similarly, when the bag-type borehole  
Figure 14: The comparison of negative pressure in the borehole.  
scaling device is applied, the negative pressure is also higher than that using the traditional sealing technology.  
Conceptualization, J.Z., Y.Z. and X.Z.; methodology, J.Z.; software, J.Z.; validation, J.Z.; formal analysis, J.Z.; investigation, J.Z.; resources, J.Z.; data curation, J.Z.; writing--original draft preparation, J.Z.; writing--review and editing, Y.Z., X.Z., M.W., S.L., Z.Y. and L.Z.; visualization, J.Z.; supervision, J.Z.; project administration, J.Z.; funding acquisition, J.Z. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Open Research Fund of State Key Laboratory of Coking Coal Exploitation and Comprehensive Utilization, China Pingmei Shenma Group, grant NO. 41040220201132T, the National Key R&D Program of China, grant No. 2022 YFE0129100, the National Natural Science Foundation of China, grant No.52061135111 and the China Postdoctoral Science Foundation, grant No. 2022M723396.  
Not applicable.  
The data presented in this study are available upon request from the corresponding author.  
The authors declare no conflict of interest.