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| Titel |
Analysis of infiltration, seepage processes and slope instability mechanisms during the November 2000 storm event in Tuscany |
| VerfasserIn |
V. Tofani, S. Dapporto, P. Vannocci, N. Casagli |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7340
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| Digitales Dokument |
URL |
| Erschienen |
In: 6th Plinius Conference on Mediterranean Storms (2004) ; Nr. 2 (2005-09-15), S.301-304 |
| Datensatznummer |
250000336
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| Publikation (Nr.) |
 copernicus.org/adgeo-2-301-2005.pdf |
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| Zusammenfassung |
| On the days 20-21 November 2000, a storm of exceptional intensity triggered
over 50 landslides within the province of Pistoia in Tuscany (Italy). These
failures are mostly of complex type, originating as rotational or
translational landslides, and transforming into flows. Two of these
landslides were investigated in this paper by modelling the ground water
infiltration process, the pore water pressure variations, both positive and
negative, and the effects of these variations on slope stability during the
rainfall event. Morphometric and geotechnical analyses were carried out for
both sites through a series of in-situ and laboratory tests, the results of
which were used as input for the modelling process. In a first step the
surface infiltration rate was simulated using a modified Chu (1978) approach
for the Green and Ampt (1911) equations in case of unsteady rainfall
together with a surficial water balance. A finite element seepage analysis
for transient conditions was then employed to model the changes in pore
water pressure during the event, using the computed infiltration rate as the
ground surface boundary condition. Finally, once again using the data from
the previous step as input, the limit equilibrium Morgenstern-Price (1965)
slope stability method was applied to calculate the variations in the factor
of safety during the event and thereby determine the most critical time of
instability. In both sites this method produced a curve for the factor of
safety that indicated that the most critical time for failure occurred a few
hours after the peak of rainfall. |
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