Effects of entrainment phenomenon on the rapid and long-runout movement of landslides in Wenjia gully, Sichuan, China
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ORIGINAL ARTICLE
Effects of entrainment phenomenon on the rapid and long‑runout movement of landslides in Wenjia gully, Sichuan, China Jiayuan Zhou1 · Hong Xu2 · Haiqing Yang1,2 · Xinchang Liu1 Received: 31 March 2020 / Accepted: 10 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract As a common phenomenon in landslides, entrainment of loose bed material along the sliding path can enhance both the volume and mobility of the sliding mass, posing a great threat to the life and property safety of people in the affected area. For the purpose of revealing the mechanism of entrainment phenomenon of sliding material in the runout process, a dynamic slice-based model was firstly proposed in the present study. In this model, the motion of landslide body is assumed to follow the rheological law proposed by Voellmy. Additionally, through Voellmy model, the increase in kinetic energy, mass and volume of landslide body and entrainment depth caused by the entrainment phenomenon were taken into consideration. Subsequently, on the basis of the dynamic slice-based model, back-analyses were performed on the Wenjia gully landslide. The effect of entrainment phenomenon on the post-failure motion was analyzed. The calculated results shows that the travel distance obtained from proposed model is closer to field data than that resulted from Scheidegger’s empirical method. Moreover, the peak value of the maximum velocity calculated by this model is in good agreement with that get from the dynamic analysis model (DAN3D). When considering the entrainment phenomenon, the volume of sliding mass increases greatly in post-failure motion. This paper provides a new method for analyzing the entrainment phenomenon in landslide motion. Keywords Landslides · Entrainment · Dynamic slice-based model · Wenjia gully landslide · Post-failure motion List of symbols b Width of slice eij Components of the strain rate tensor exx Mean strain rate in the x direction ezz Mean strain rate in the z direction Ek Kinetic energy of slice k h Height of slice W Weight of slice m Mass of slice mk The mass of the slice k N Normal force acting on the base of the slice P Interslice force t Previous time * Haiqing Yang [email protected] 1
School of Civil Engineering, Chongqing University, Chongqing 400045, China
National Breeding Base of Technology and Innovation Platform for Automatic-monitoring of Geologic Hazards, Chongqing Engineering Research Center of Automatic Monitoring for Geological Hazards, Chongqing 400042, China
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T Basal shear resistance v Velocity of sliding mass v̄ Average velocity along the sliding surface v̄ k Average velocity of slice k Ẇ k The sum of the rate of work done by body force, surface force, and energy dissipation due to deformation of slice k Z Thickness of sliding mass Zb Thickness of bed-sediment 𝜙 Friction angle of sliding surface 𝜙b Friction angle of bed-sediment γ Unit weight of sliding mass γb Unit weight of bed-sediment θ Dip angle of slope θL Inclination between
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