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| Titel |
The effect of groundwater fluctuations on the velocity pattern of slow-moving landslides |
| VerfasserIn |
Th. W. J. Asch, J.-P. Malet, T. A. Bogaard |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 9, no. 3 ; Nr. 9, no. 3 (2009-05-18), S.739-749 |
| Datensatznummer |
250006782
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| Publikation (Nr.) |
 copernicus.org/nhess-9-739-2009.pdf |
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| Zusammenfassung |
Slow-moving landslides show complex mechanical and fluid
interactions. They show among others non linear intrinsic viscosity of the
shear zone, undrained loading effects and the generation of excess pore
water pressure. The parameterization of hydrological and geomechanical
factors by field and laboratory tests to describe the movement pattern of
these landslides is difficult. It is a challenge to simulate accurately the
de- and acceleration of these landslides and particularly, to forecast
catastrophic surges.
In this paper the relation between groundwater fluctuation and landslide
velocity for two deep-seated landslides of the Trièves Plateau (the
Monestier-du-Percy landslide and the Saint-Guillaume landslide) is analysed. Inclinometer measurements,
showing the displacement in depth after 1–2 months periods, showed on both
landslides shear band deformation within 1 m. At the Monestier-du-Percy landslide, depending
on the position, the shear band depths vary between 25.0 m and 10.0 m. At
the Saint-Guillaume landslide, the inclinometers detected several slip surfaces inside the
clays, at respectively 37.0 m, 34.5 m, and 14.0 m depth. Two simple
geomechanical models are developed to describe these displacements in depth
in relation to measured groundwater fluctuations. Calibration of the models
using the friction angle delivered no constant values for different
measuring periods. It appeared that calibrated (apparent) friction values
increase with increasing groundwater levels. The paper discusses the
possibility of the generation of negative excess pore water pressures as a
feed back mechanism, which may explain the complex displacement pattern of
these landslides developed in varved clays. |
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