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Study on the rainfall and aftershock threshold for debris flow of post-earthquake

  • Siming HeEmail author
  • Dexin Li
  • Yong Wu
  • Yu Luo
Article

Abstract

Due to the special condition of provenance and disaster environment after “5·12” Earthquake, the probability and conditions of the occurrence of gully debris flow change greatly after the event, which make it difficult to prevent disaster effectively. In this study the hydrological model of ground water table in loose sediment is established. According to infinite slope theory, the safety factor of deposits is defined as the ratio of resistance force to driving force. The starting condition of post-earthquake gully debris flow is clearly studied by analyzing the effects of rainfall intensity, seismic strength, slope gradient and mechanical properties on the balance of accumulation body. Then the formulas of rainfall and aftershock threshold for starting of gully debris flow are proposed, and an example is given to illustrate the effect of rainfall, aftershocks and their coupling action on a debris flow. The result shows the critical rainfall intensity decreases as the lateral seismic acceleration and channel gradient increases, while the critical intensity linearly increases as the friction angle increases.

Keywords

Earthquake Hydrological model Debris flow Rainfall threshold 

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Copyright information

© Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  1. 1.Key laboratory of Mountain Hazards and Earth Surface ProcessChinese Academy of ScienceChengduChina
  2. 2.Institute of Mountain Hazards and EnvironmentChinese Academy of ScienceChengduChina

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