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Titel |
Infiltration, seepage and slope instability mechanisms during the 20-21 November 2000 rainstorm in Tuscany, central Italy |
VerfasserIn |
V. Tofani, S. Dapporto, P. Vannocci, N. Casagli |
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 ; 6, no. 6 ; Nr. 6, no. 6 (2006-12-12), S.1025-1033 |
Datensatznummer |
250003813
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Publikation (Nr.) |
copernicus.org/nhess-6-1025-2006.pdf |
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Zusammenfassung |
On 20–21 November 2000, a storm of high intensity, with a estimated return
period of more than 100 years, triggered over 50 landslides within the
province of Pistoia in Tuscany (Italy). These failures can be defined as
complex earth slides- earth flows. One of the documented landslides has been
investigated by modelling the ground water infiltration process, the
positive and negative pore water pressure variations and the effects of
these variations on slope stability during the rainfall event. Morphometric
and geotechnical analyses were carried out through a series of in-situ and
laboratory tests, the results of which were used as input for the modelling
process. The surface infiltration rate was initially simulated using the
rainfall recorded at the nearest raingauge station. Finite element seepage
analysis for transient conditions were then employed to model the changes in
pore water pressure during the storm event, using the computed infiltration
rate as the ground surface boundary condition. Finally, the limit
equilibrium slope stability method was applied to calculate the variations
in the factor of safety during the event and thereby determine the critical
time of instability. For the investigated site the trend of the factor of
safety indicates that the critical time for failure occurs about 18 h
after the storm commences, and highlights the key role played by the soil
permeability and thickness in controlling the response in terms of slope
instability. |
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