## 6 Conclusions  
1. As the tunnel face approached the water-rich fault fracture zone, the displacement at each monitoring point in the water-resistant rock mass increased continuously. The closer the tunnel was to the fault, the greater the increase rate of the displacement was at each monitoring point in the water-resistant rock mass. When the tunnel was excavated to the position 5 m from the fault, a sudden displacement of the center of the face was observed. The water-resistant rock mass ahead of the face was damaged, and the tunnel was subjected to a water inrush disaster. The recommended safety thickness of the water-resistant rock mass was 5-6 m.
2. When the tunnel face was far away from the fault, the water-resistant rock mass at the face was less affected by the water pressure, and it was in a relatively stable state. As the tunnel face approached the fault, water seepage from the fault occurred, and the water entered the water-resistant rock mass through the fissures. Since the face was jointly affected by excavation disturbance and fissure water pressure, the water pressure encountered a slow decline trend with the excavation of the face.
3. The middle bench of the 2# adit of Xianglushan tunnel was first excavated and supported to the face, and a grouting wall was applied to the face. The range of the grouting reinforcement circle was 6 m outside the excavation profile, and the length of cyclic grouting was 30 m. The length of cyclic excavation was 25 m, and a 5 m long grouting rock disc was retained in each cycle. Grouting slurry was cement slurry with a water-cement mass ratio (W/C ratio) of 0.5-1:1.
4. The evaluation of the grouting effect by means of drilling acoustic wave, drilling TV, and radar detection confirmed that the grouting treatment scheme had an excellentreinforcement effect on the rock mass. The deformation modulus of the rock mass after grouting was increased by 37-53%. The rock mass possessed a better elastic deformation capacity to external loads, which slowed down the deformation process of the rock mass. The shear strength parameters (cohesion c and friction coefficient tan\(\varphi\)) were increased by 10-14%, which enhanced the overall adhesion and improved the shear and sliding resistance of the rock mass.  
Conceptualization, [PERSON] ([PERSON]) and F.C.; methodology, [PERSON] ([PERSON]); software, [PERSON] ([PERSON]); validation, [PERSON] ([PERSON]), F.C. and J.L.; formal analysis, [PERSON] ([PERSON]); investigation, F.C.; resources, J.L.; data curation, F.C.; writing--original draft preparation, [PERSON] ([PERSON]); writing--review and editing, [PERSON] ([PERSON]); visualization, F.C.; supervision, J.L.; project administration, J.L.; funding acquisition, [PERSON] ([PERSON]). All authors have read and agreed to the published version of the manuscript.  
This study was funded by the National Natural Science Foundation of China (Grant Nos. 52178388, 42307259) and Yunnan Province Major Science and Technology Special Plan Project (Grant No. 202002 AF080003).  
Data are contained within the article.  
The authors greatly appreciate the financial support from funding bodies and would be grateful to the reviewers for their valuable comments and suggestions to improve the quality of the paper.  
The authors declare no conflicts of interest.