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Simulated effect of soil depth and bedrock topography on near‐surface hydrologic response and slope stability
Author(s) -
Lanni Cristiano,
McDonnell Jeff,
Hopp Luisa,
Rigon Riccardo
Publication year - 2013
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.3267
Subject(s) - bedrock , geology , landslide , slope stability , geomorphology , pore water pressure , slip (aerodynamics) , subsurface flow , geotechnical engineering , hydrology (agriculture) , soil science , groundwater , physics , thermodynamics
This paper explores the effect of hillslope hydrological behavior on slope stability in the context of transient subsurface saturation development and landslide triggering. We perform a series of virtual experiments to address how subsurface topography affects the location and spatial pattern of slip surface development and pore pressure dynamics. We use a 3D Darcy–Richards equation solver (Hydrus 3‐D) combined with a cellular automata slope stability model to simulate the spatial propagation of the destabilized area. Our results showed that the soil–bedrock interface and in particular, bedrock depressions, played a key role in pore pressure dynamics, acting as an impedance for the downslope drainage of perched water. Filling and spilling of depressions in the bedrock surface microtopography induced localized zones of increased pressure head such that the development of pore‐pressure fields—not predictable by surface topography—lead to rapid landslide propagation. Our work suggests that landslide models should consider the subsurface topography in order to include a connectivity component in the mathematical description of hydrological processes operating at the hillslope scale. Copyright © 2012 John Wiley & Sons, Ltd.