# Numerical Study on Redbed Slope Stability Under Multi-Factor Conditions
## 6 Conclusions  
This study investigates a high road-cut slope in a redbed region, establishing numerical models to simulate the effects of excavation, seismic activity, and rainfall on slope stability. Based on the numerical calculations, the following conclusions are drawn:  
1. The use of a contact surface model to simulate sliding effects between rock layers yielded results that closely matched actual monitoring data, validating the model's reliability in capturing the deformation behavior of redbed slopes.
2. Following excavation, the redbed slope did not exhibit large-scale collapses or landslides. However, localized failures and displacements occurred at the slope crest within the strongly weathered zones and weak interlayers. With a safety factor of 1.58, the slope's overall stability remains within acceptable limits under static conditions.
3. Under strong seismic loading, the displacement of the slope was positively correlated with the input acceleration, with the soil-rock mass amplifying acceleration effects, particularly in the vertical direction. Shear failure was concentrated near contact surfaces, with pronounced landslide risks identified in strongly weathered zones and shallow layers adjacent to these interfaces.
4. Rainfall-induced instability primarily manifested as shear failure along the strongly weathered mudstone and sandy shale zones, with pronounced sliding observed at the slope crest. The reduction in rock strength due to saturation was the dominant factor driving slope instability under prolonged rainfall.
5. As rainfall duration increased, slope displacements evolved significantly, and the potential sliding surface deepened. This led to the formation of a continuous sliding surface along weak interlayers, increasing the likelihood of large-scale slope failure.  
These findings underscore the necessity of incorporating geological characteristics, environmental factors, and dynamic disturbances into slope stability assessments for redbed regions. Effective mitigation strategies, such as targeted reinforcement of weak interlayers and improved drainage systems, are crucial for ensuring long-term stability in similar engineering projects. Future research should focus on incorporating sensitivity analysis to evaluate the impact of input parameter variations, conducting more comprehensive field experiments to validate the model, and exploring the effects of multi-field coupling. These efforts will contribute to a more robust understanding of slope stability in redbed regions and enhance the accuracy and reliability of future engineering designs.  
Conceptualization, J.W. and H.W.; methodology, H.W. and H.L.; software, H.W. and T.P.; validation, H.W., H.L. and T.P.; formal analysis, H.W. and T.P.; investigation, H.L. and T.P.; resources, J.W.; data curation, H.W.; writing--original draft preparation, H.W.; writing--review and editing, J.W.; visualization, H.W.; supervision, J.W.; project administration, J.W.; funding acquisition, J.W. All authors have read and agreed to the published version of the manuscript. This research was funded by the National Foreign Expert Project (Grant No. DL2023036001L) and the Sichuan Science and Technology Program (Grant No. 2024 JDHJ0019).  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The original contributions presented in this study are included in the article. Further inquiries may be directed to the respective author.  
**Acknowledgments:** The authors would like to express their gratitude to the editor for their valuable guidance and support throughout the publication process. Special thanks are also extended to the anonymous peer reviewers for their constructive comments and insightful suggestions, which have significantly improved the quality of this work.  
**Conflicts of Interest:** The authors declare no conflicts of interest.