Performance of landslide debris-resisting baffles

Arrays of landslide debris baffles are commonly installed upstream of rigid barriers in Hong Kong to dissipate flow energy impacting a rigid barrier. Currently, baffles are installed using prescriptive and empirical approaches in Hong Kong without design recommendations. Given the engineering value of baffles, an improved understanding of their interaction mechanisms is warranted. Flume modelling and numerical back analysis using the discrete element method (DEM) were adopted to study the influence of landslide debris baffles on impact on a downstream terminal rigid barrier. Froude scaling was used to dynamically characterise the flow. The optimum geometrical configuration was examined. The results revealed that an array of baffles is effective in reducing the peak dynamic impact induced by debris on a rigid barrier and that overflow processes need to be controlled. Baffle heights exceeding 1.5 times the approach flow depth (h) exhibited little incremental influence on reducing the peak dynamic impact forces induced on the rigid barrier. At least two staggered rows are required to effectively intercept discharge from the first row and reduce the frontal debris impact force. The optimum spacing between successive rows (L) and transverse blockage is L/D = 3 (D is the slit opening) and 30%, respectively.

[1]  D. C. Rapaport,et al.  The Art of Molecular Dynamics Simulation , 1997 .

[2]  Sebastian Noelle,et al.  Shock waves, dead zones and particle-free regions in rapid granular free-surface flows , 2003, Journal of Fluid Mechanics.

[3]  C. Wendeler,et al.  DESIGN OF FLEXIBLE DEBRIS FLOW BARRIERS , 2011 .

[4]  Peter Gauer,et al.  The design of avalanche protection dams : recent practical and theoretical developments , 2009 .

[5]  H. Wang,et al.  Assessment of risk from rockfall from active and abandoned quarry slopes , 1995 .

[6]  C. Ng,et al.  Physical modeling of baffles influence on landslide debris mobility , 2015, Landslides.

[7]  C. Ng,et al.  Flume investigation of landslide granular debris and water runup mechanisms , 2015 .

[8]  Discrete-element investigation of influence of granular debris flow baffles on rigid barrier impact , 2016 .

[9]  Charles Wang Wai Ng,et al.  Computational investigation of baffle configuration on impedance of channelized debris flow , 2015 .

[10]  M.G.B. Drew,et al.  The art of molecular dynamics simulation , 1996 .

[11]  Adrian E. Scheidegger,et al.  On the prediction of the reach and velocity of catastrophic landslides , 1973 .

[12]  A. Azzoni,et al.  Experimentally gained parameters, decisive for rock fall analysis , 1995 .

[13]  Ronaldo I. Borja,et al.  DEM simulation of impact force exerted by granular flow on rigid structures , 2011 .

[14]  SongD..  Flume investigation of landslide debris–resisting baffles , 2014 .

[15]  Kolumban Hutter,et al.  Avalanche dynamics: Dynamics of rapid flows of dense granular avalanches , 2016 .

[16]  J. J. Wu,et al.  Coefficient of restitution and rotational motions of rockfall impacts , 2002 .

[17]  A. Armanini,et al.  Dynamic impact of a debris flow front against a vertical wall , 2011 .

[18]  Yongqi Wang,et al.  Velocity measurements in dry granular avalanches using particle image velocimetry technique and comparison with theoretical predictions , 2005 .

[19]  A. Heim.  Bergsturz und Menschenleben , 1932 .