## 5 Conclusions  
In this paper, the mechanical properties of basalt fibre-reinforced microbially consolidated soil were studied by conducting unconfined compressive strength tests and direct shear tests and analysing the stability of the slope after microbial reinforcement in terms of plastic zone characteristics, displacement clouds, and safety factors through finite element numerical simulations. The following conclusions were obtained:  
1. The combination of fibre reinforcement technology and MICP technology can significantly improve the compressive and shear strength of the soil and improve the characteristics of brittle soil after microbial curing.
2. The incorporation of basalt fibres has an important influence on the mechanical properties of denittifying bacterial consolidated soil. When the fibre admixture is low, the unconfined compressive strength of the soil increases with increasing fibre length, and when the fibre admixture is high, the strength tends to increase and then decrease with increasing fibre length. The optimal fibre admixture is between 0.3 and 0.4, and the best fibre length is 12 mm.
3. The effect of increasing basalt fibre incorporation on the calcium carbonate content of the soil after microbial curing tends to increase and then decrease. This is because after the fibre is added to the soil, the area where calcium carbonate can be colonised increases, and when the fibre is increasingly added, the internal void of the soil is gradually occupied by the fibre, and the growth of microorganisms is restricted. This has a negative impact on the generation of calcium carbonate.
4. The development of the plastic zone of the slope before and after microbial reinforcement is generally similar, but the scope of the plastic zone after reinforcement is reduced as a whole, especially in the reinforced area of the slope, and the maximum equivalent plastic stress is decreased by 65 kPa.
5. The safety coefficient of the slope before microbial reinforcement was 1.16, and the safety coefficient after reinforcement was 1.41. The stability of the slope was obviously strengthened.  
Conceptualization, W.J. and W.Y.; methodology, W.J.; software, W.J.; validation, W.J., W.Y. and L.Z.; formal analysis, W.J.; investigation, W.J.; resources, W.Y.; data curation, L.Z.; writing--original draft preparation, W.J.; writing--review and editing, W.J.; visualization, W.J.; supervision, W.J.; project administration, W.J.; funding acquisition, W.Y. All authors have read and agreed to the published version of the manuscript.  
Figure 14: Relationship between safety factor and lateral displacement after microbial reinforcement.  
**Funding:** This research was funded by Hunan Provincial Transportation Science and Technology Project. The project names are \"Research on Key technologies of Road slope Ecological landscape restoration in ecologically fragile Areas\" and \"Research on microbial improvement of ecological protection technology for strongly weathered coal gangue slopes\", grant numbers are 201803 and 202212 respectively.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** All data, models, and code generated or used during the study appear in the submitted article.  
**Conflicts of Interest:** The authors declare that they have no conflict of interest.