# Experimental Study on Grouting Visualization of Cover Layer Based on Transparent Soil
## 6 Conclusions  
1. This study selects transparent soil materials capable of simulating the cover layer and designs a visual testing apparatus for grouting simulation within the cover layer. The results demonstrate that the transparent soil, in combination with the model box, offers a clear observation window for grouting, providing superior visualization and intuitiveness compared to traditional grouting tests. This facilitates detailed observation of grout flow dynamics and diffusion patterns within the cover layer. The use of transparent soil materials for analyzing grout diffusion in cover layers is thus demonstrated to be feasible.
2. A non-contact monitoring method for grout diffusion in cover layers, based on transparent soil materials and stable slurry, has been developed. Based on digital image technology, this method allows for real-time monitoring of grout diffusion patterns. This visual testing approach overcomes the limitations of traditional contact-based methods and provides significant advantages for continuous observation and dynamic characterization of grout diffusion morphology throughout the grouting process.
3. Based on a self-developed transparent soil visual grouting model device, a stepwise pressure grouting test was conducted to investigate the slurry diffusion morphology and the velocity field distribution characteristics of transparent soil under varying grouting pressures. Preliminary observations indicated that the splitting of the formation was accompanied by a compaction process during the grouting procedure. This device provides a valuable reference for the design of similar cover layer grouting test systems and for further research on visualized slurry diffusion.
4. In this transparent soil test, the grouting experiment was carried out under the condition of a large scale. The stable grout was used to implement single-hole pressure grouting, and the diffusion law of grout under the condition of step pressure was obtained. In view of the fact that multiple rows of porous grouting are mostly used in the grouting project of the overburden, based on this study, porous grouting tests can be carried out in the future by improving the structural strength and sealing performance of the model box, and the influence mechanism of pore sequence on the slurry diffusion behavior can be discussed in depth, so as to provide a reference for the formulation of the construction sequence and pressure control strategy of porous grouting.  
Writing--review & editing, P.G.; Writing--review & original draft, W.Z. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Doctoral Student Innovation Fund of China Institute of Water Resources and Hydropower Research, grant number BS202302. And The APC was funded by Special scientific research project of China Institute of Water Resources and Hydropower Research, grant number EM0145B022021.  
Not applicable.  
The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author. The data are not publicly available due to privacy.  
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.