Parametric Analysis of Factors that Affects the Rainfall Induced Slope Stability

Year 2022, , 49 - 57, 30.12.2022

Furkan Veli Özçelik , Murat Ergenokon Selçuk

https://doi.org/10.48053/turkgeo.1062245

Cited By: 2

Abstract

Slope failures are one of the most vital problems in geotechnical engineering applications which may cause damage both in human life and financial. Slope failures are frequently observed especially in regions where rainfall is high. The most important factor affecting slope stabilities is rainfall infiltration. It is known that infilled soils are generally unsaturated soil. Therefore, the analysis of infill slopes should be performed within the scope of unsaturated soil mechanics. Rainfall infiltration causes the groundwater level to rise, which reduces the shear strength of the soil causing slope instability. In this study, the effect of rainfall intensity, rainfall duration, soil permeability, groundwater level, cohesion of soil, internal friction angle of the soil, and slope angle of the slope on the slope stability were analyzed parametrically by using GEOSTUDIO software. The infiltration analyses were performed using Seep/w module and factor of safety number of unsaturated soil slope were determined using Morgenstern method of Slope/w module of GEOSTUDIO software. Furthermore, different factor of safety numbers was found for each analysis along with the interpretation of the parameters effecting the slope stability. The results obtained in the present investigation showed that the rainfall intensity affects the stability of the slope. It was determined that there existed a non-linear relationship between rainfall intensity and safety number. As the rainfall intensity increases, the negative pore water pressure in the soil decreases nonlinearly, and the factor of safety number of the slope similarly decreases by 10% relative to the initial condition. When the rainfall duration change was taken into account, it was found that short time-heavy rainfalls affected the slope stability more than long time-low density rainfalls. Moreover, slope angle significantly influenced slope stability. It was observed that when the slope angle increased from 40° to 50°, factor of safety number decreased by 18.34%.

Keywords

Slope stability, Rainfall infiltration, Unsaturated soil, Shear strength

Supporting Institution

This study was presented in IMSEC 2021

References

• Aslan Fidan, A. (2017). Doygun olmayan koşullarda yağış infiltrasyonu etkisindeki şevlerin stabilite analizi. (MSc thesis). Dicle University, Diyarbakır, Turkey (in Turkish).
• Au, S.W.C. (1998). Rain-induced slope instability in Hong Kong. Engineering Geology, 51(1), 1-36.
• Fredlund, D.G. (2012). Unsaturated soil mechanics in engineering practice. Journal of geotechnical and geoenvironmental engineering, 132(3), 286-321.
• GEOSLOPE (2012). Stability Modeling with Slope/w. Canada.
• GEOSLOPE (2015). Seepage Modeling with Seep/w.
• Jeong, S., Lee, K., & Kim, J. (2017). Analysis of Rainfall-Induced Landslide on Unsaturated Soil Slopes. Sustainability, 9(7), 1280.
• Karabulut, B. (2019). Yağış ile Sızmanın Şevlerin Stabilitesine Etkisi . (MSc thesis). Yıldız Technical University, İstanbul, Turkey (in Turkish).
• Önalp, A., & Arel, E. (2013). Geoteknik bilgisi I zeminler ve mekaniği çözümlü problemlerle. Birsen Yayınevi, İstanbul, 461.
• Tetik, A. (2020). Yağış etkisi altındaki şevlerin stabilite analizi (MSc thesis). Manisa. Celal Bayar University, Manisa, Turkey (in Turkish).
• Wang, Y., Chai, J., Cao, J., Qin, Y., Xu, Z., & Zhang, X. (2020). Effects of seepage on a three-layered slope and its stability analysis under rainfall conditions. Natural Hazards, 102(3), 1269-1278.