Journal of the Korean GEO-environmental Society (한국지반환경공학회 논문집)

Korean Geo-Environmental Society (한국지반환경공학회)
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A Study on Rainfall Induced Slope Failures: Implications for Various Steep Slope Inclinations

  • Do, Xuan Khanh (Department of Civil Engineering Chungnam National University) ;
  • Jung, Kwansue (Department of Civil Engineering Chungnam National University) ;
  • Lee, Giha (Department of Construction and Disaster Prevention Engineering, Kyungpook National University) ;
  • Regmi, Ram Krishna (Institute for the Advanced Study of Sustainability, United Nations University)
  • Received : 2016.01.04
  • Accepted : 2016.04.04
  • Published : 2016.05.01
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Abstract

A rainfall induced slope failure is a common natural hazard in mountainous areas worldwide. Sudden and rapid failures which have a high possibility of occurrence in a steep slope are always the most dangerous due to their suddenness and high velocities. Based on a series of experiments this study aimed to determine a critical angle which could be considered as an approximate threshold for a sudden failure. The experiments were performed using 0.42 mm mean grain size sand in a 200 cm long, 60 cm wide and 50 cm deep rectangular flume. A numerical model was created by integrating a 2D seepage flow model and a 2D slope stability analysis model to predict the failure surface and the time of occurrence. The results showed that, the failure mode for the entire material will be sudden for slopes greater than $67^{\circ}$; in contrast the failure mode becomes retrogressive. There is no clear link between the degree of saturation and the mode of failure. The simulation results in considering matric suction showed good matching with the results obtained from experiment. A subsequent discarding of the matric suction effect in calculating safety factors will result in a deeper predicted failure surface and an incorrect predicted time of occurrence.

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References

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