## 5 Conclusions  
This study examined the pore water pressure responses and stability of an unsaturated-saturated consolidating slope under the influence of rainfall infiltration. An analysis of slope behaviour was carried out with the results obtained for soils having similar saturated coefficients of permeability (\(k_{s}\)) of 1 \(\times\) 10\({}^{-5}\) m/s, SWCC fitting parameters (\(n_{f}\) of 2, and \(m_{f}\) of 1), and rainfall flux (\(q\)) of 1 \(\times\) 10\({}^{-6}\) m/s (i.e., \(q/k_{s}\) of 0.1) but with varying air-entry and coefficient of volumetric compression (mv) values. The following are major highlights of the study:  
1. For the unsaturated portion of the slope (above the groundwater table), negative pore water pressure during rainfall infiltration less than the coefficient of permeability of the soil increases with the air-entry values of the soil, indicating the existence of suction in this region. However, as the time of rainfall progresses, the matric suction values tend to reduce with increasing air-entry values.
2. Generally, it is noticed that an increase in soil compressibility does tend to result in a decrease in soil suction above the rising groundwater level, irrespective of the advancing groundwater level for rainfall less than the saturated permeability of the soil and lasting for prolonged periods.
3. The difference in the pore water distribution profiles seems less for mv values below 0.002 kPa\({}^{-1}\) especially for major rainfall events. Moreover, the distribution of the soil suction profile seems marginal for infiltration durations of 1 h to 4 h.
4. In terms of the stability of the slope, the factor of safety does appear to reduce with an increment in infiltration time as soil compression increases. This difference is slightly more pronounced (especially for antecedent rainfall with duration from 7 days to 30 days).
5. Although the slope appears to be just safe (factor of safety of 1.2) under the conditions of increased air-entry value, increased compression, and rainfall flux of 1 \(\times\) 10\({}^{-6}\) m/s, the stability of the slope can be compromised if the rainfall flux is equal to or greater than the saturated coefficient of permeability of the soil.  
Figure 12: Factor of safety vs. rainfall durations for different \(m_{v}\) values.  
**Author Contributions:** Conceptualization, E.E. and S.A.; methodology, E.E.; software, E.E.; validation, S.A.; formal analysis, E.E.; investigation, S.A.; resources, E.E.; data curation, E.E.; writing--original draft preparation, E.E.; writing--review and editing, S.A.; visualization, E.E.; supervision, S.A.; project administration, S.A.; funding acquisition, E.E. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
**Data Availability Statement:** The data presented in this study are available in article.  
**Acknowledgments:** The authors would like to thank the University of the West of England (UWE), Bristol, UK, for the Vice-Chancellor's Early Career Researcher Development grant and the staff at the Research, Business, and Innovation unit of the same university for their support in making this study possible.  
**Conflicts of Interest:** The authors declare no conflict of interest.