# Study on the Stability and Control of Gob-Side Entry Retaining in Paste Backfill Working Face
## 7 Conclusions  
This study investigates the stability of GER with paste backfill working faces. The main conclusions are as follows:  
1. The theoretical analysis examined the movement characteristics of the overlying strata in mining fields with varying backfill ratios. The results indicate that as the backfill ratio increases, the distance from the gob area to the overlying roof and the space for roof subsidence becomes more limited. The backfill material significantly restricts the subsidence of the immediate roof and main roof, reducing the likelihood of fractures in these strata.
2. Numerical simulations were employed to analyze the deformation of the surrounding rock and the manifestation of mining-induced stress in the roadway with different backfill ratios. The analysis reveals that when the backfill ratio reaches 95%, the support of the backfill is enhanced, leading to a significant reduction in the deformation of surrounding rock of CT301 headgate. Roof subsidence, uneven deformation, and bulging phenomena are not prominent, while the deformation of the two ribs is minimal, ensuring excellent structural integrity. The degree of mining-induced stress manifestation is lessened, and the surrounding rock stability improves.
3. A numerical simulation was conducted to analyze the evolution of abutment stress in the mining field. The results show that as the distance of advancement increases, the bearing capacity of the paste backfill improves. The backfill material and the overlying strata gradually form a stable cohesive system, leading to a stabilization of the abutment stress in the mining field.
4. A comprehensive control technology system with basic bolt-mesh-cable support structure and localized portal hydraulic supports reinforcement was applied. Measurement stations were arranged along the CT301 headgate. The results show that the surrounding rock stabilizes at a distance of 80 m from the working face. The maximum deformation of roof and floor, as well as the two ribs, are controlled at approximately 190 mm and 140 mm, respectively. The deformation of the surrounding rock is maintained within safe limits, ensuring a significant improvement in the stability and effectiveness of GER. However, this study also has certain limitations, as outlined below:  
Figure 18: Deformation monitoring of roadway.  
In practical engineering, the performance of the backfill material may be influenced by factors such as temperature, humidity variations, and long-term stability in the underground environment. This study did not explore these factors in depth.
* While the impact of backfill rate was discussed, other important factors affecting the stability of GER, such as mining depth and geological heterogeneity, were overlooked. These factors can significantly affect the filling effect and surrounding rock stability. Neglecting them may lead to an incomplete understanding of the stability mechanisms of surrounding rock.  
C.X.Writing--original draft, Data curation, Resources. X.W.: Project administration, Visualization. D.C. and G.W. Supervision. Z.N. and H.L.: Software. All authors have read and agreed to the published version of the manuscript.  
This research was financially supported by National Key Research and Development Program of China (2023 YFC2907600), National Natural Science Foundation of China (52174132), Postgraduate Research and Practice Innovation Program of Jiangsu Province (KYCX24_2852), Graduate Innovation Program of China University of Mining and Technology (2024 WLKXJ018).  
Not applicable.  
The data that support the findings of this study are available from the corresponding author, upon reasonable request.  
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.