INFLUENCE OF SHEAR SURFACE GEOMETRIES AND MECHANICAL STRENGTH PARAMETERS ON DEFORMATION PROCESSES IN MASSIVE LANDSLIDES

Rock Engineering 2009 - Rock Engineering in Difficult Conditions
Mark Diederichs, Jean Hutchinson,
Abstract Massive landslides display complex deformation processes. For instance, slope movements of the Downie Slide, monitored using borehole inclinometers, extensometers, and survey monuments, show considerable spatial and temporal inconsistencies in the displacement rates. This study assesses the influence that inferred shear surface geometry and mechanical strength parameters, which are key factors contributing to variable slope movements, have on resolving spatially and temporally discriminated slope deformations in three-dimensions. Borehole data defines the shear surface location at discrete points within the slide and there is some, very limited, information available on strength parameters. The shear surface geometry and mechanical rockmass characteristics for the extent of the slide must, therefore, be largely inferred. A series of three-dimensional numerical simulations have been run to account for different interpretations of both the shear surface geometry and the spatial distribution of shear strength parameters. When the observed field displacement data are reproduced through numerical simulation the model can be interpreted to provide valuable insight into which parameters play key roles in slope behavior. This investigation illustrates the importance of rigorous geospatial definition of slip surface geometry and mechanical properties, and the value of three-dimensional modelling.
Keywords: Numerical modelling, landslide geomechanics
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