## 6 Conclusions  
(1) The key to gob-side entry retaining technology with intensive borehole roof cutting is to determine reasonable roof cutting parameters (roof cutting height, roof cutting angle, aperture and hole spacing). The control mechanism of each parameter on the roof is analyzed and the numerical simulation is obtained:  
1 When the borehole cannot penetrate the basic roof strata, the greater the roof cutting height, the easier it is to break the roof, but a higher roof cutting height is not necessarily better. When the roof cutting height exceeds the roof control height of the constant-resistance anchor cable, the peak stress, influence range and load-increase coefficient of the coal pillar side increase, and stress concentration is formed in the advanced section of the roadway. According to the theory of broken expansion, the height of the cutting top is calculated to be H > 7.3 m.  
2 When the roof cutting angle is small, the roof of the gob is hinged with the roof of the roadway, and the roadway forming effect is poor. Increasing the roof cutting angle  
Figure 17: Scene photographs. increases the lateral cantilever length of the roof, and the rotation of the roof in the gob will increase the roof subsidence of the roadway. A cutting angle of \(\theta\geq 11.9^{\circ}\) was calculated. 3 The large aperture can increase the normal stress and shear stress on the section of the borehole. The theoretical calculation shows that the hole diameter is greater than 40 mm, and the hole diameter of 48 mm is selected according to the drilling construction standard. 4 When the aperture is 48 mm, the hole spacing should not exceed 166 mm. The smaller the hole spacing is, the higher the degree of roof weakening; it also increases the difficulty of construction and has high requirements for end support. The increase in hole spacing is not conducive to the penetration of the drilling plastic zone, and the weakening degree of the roof is limited. (2) The optimal scheme of dense-drilling roof cutting is determined: a roof cutting height of 8 m; a cutting angle of 15\({}^{\circ}\); a borehole diameter of 48 mm; drilling spacing at 200 mm. The engineering practice application was carried out at the 203 working face of the Ruineng Coal Mine. During the test, the deformation of the surrounding rock of the roadway was controllable, and the size of the roadway met the reuse conditions. The results confirm that the key parameter determination method is effective and the dense-drilling roof cutting and pressure relief gob-side entry retaining is feasible. D.L. : Conceptualization, Supervision, Project Administration and Funding acquisition. S.C.: Writing, Original Draft, Conceptualization, Methodology, Software, Validation, Data Curation, Formal analysis. H.Y. : Software, Supervision, Resources, Project Administration, Data Curation. J.Y. : Conceptualization, Supervision, Resources, Project Administration, Validation. Y.Y. : Investigation, Conceptualization, Resources, Project Administration, Formal Analysis. S.L. : Theoretical Analysis, Methodology, Investigation. B.H. : Theoretical Analysis, Methodology, Investigation. P.X. : Conceptualization, Investigation, Data Curation, Supervision. All authors have read and agreed to the published version of the manuscript. This research was supported by the Program of National Natural Science Foundation of China (Grant number: 52274137); the Program of National Natural Science Foundation of China (Grant number: 52474145); and Supported by the Excellent Youth Science Foundation of Xi'an University of Science and Technology (Grant number: 6310222012). Not applicable. Data Availability Statement: Data will be made available on request. The authors express their sincere gratitude to [PERSON] and [PERSON] for their valuable suggestions and assistance during the preparation of this study. Their contributions were instrumental in refining the research methodology and enhancing the quality of the manuscript. The authors declare no conflicts of interest.