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Titel |
Hydroacoustic monitoring of a salt cavity: an analysis of precursory events of the collapse |
VerfasserIn |
F. Lebert, S. Bernardie, G. Mainsant |
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 ; 11, no. 9 ; Nr. 11, no. 9 (2011-09-29), S.2663-2675 |
Datensatznummer |
250009685
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Publikation (Nr.) |
copernicus.org/nhess-11-2663-2011.pdf |
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Zusammenfassung |
One of the main features of "post mining" research relates to available
methods for monitoring mine-degradation processes that could directly
threaten surface infrastructures. In this respect, GISOS, a French scientific
interest group, is investigating techniques for monitoring the eventual
collapse of underground cavities. One of the methods under investigation was
monitoring the stability of a salt cavity through recording
microseismic-precursor signals that may indicate the onset of rock failure.
The data were recorded in a salt mine in Lorraine (France) when monitoring
the controlled collapse of 2 000 000 m3 of rocks surrounding a cavity at
130 m depth. The monitoring in the 30 Hz to 3 kHz frequency range highlights the
occurrence of events with high energy during periods of macroscopic
movement, once the layers had ruptured; they appear to be the consequence of
the post-rupture rock movements related to the intense deformation of the
cavity roof. Moreover the analysis shows the presence of some interesting
precursory signals before the cavity collapsed. They occurred a few hours
before the failure phases, when the rocks were being weakened and damaged.
They originated from the damaging and breaking process, when micro-cracks appear
and then coalesce.
From these results we expect that deeper signal analysis and statistical
analysis on the complete event time distribution (several millions of files)
will allow us to finalize a complete typology of each signal families and
their relations with the evolution steps of the cavity over the five years
monitoring. |
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