Mid-Magnitude-Events: A quantitative approach for run-out assessment taking fragmentation into account

B. Sellmeier, K. Thuro, M. Krautblatter

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Recent rockfall events, like the Tramin rockfall at January 21st, 2014, underline the significance of a comprehensive hazard assessment. A common way of estimating the hazard along infrastructure is the performance of run-out modelling using 3D rockfall codes like Rockyfor3D or RAMMS::Rockfall (Dorren, 2010, Bartelt et al., 2013). The potential block volumes are often roughly estimated from talus material and an overview of the source area, where the magnitude assessment is usually physically and intellectually demanding. Nevertheless especially for increased magnitudes, the volume estimation is crucial in terms of hazard analysis. Mid-Magnitude-Events exceed the load capacity of the most mitigation measures and their date of failure is hard to predict. Here we define the term Mid-Magnitude-Events as block volumes between boulder falls (10-100 m3) and block falls (100-10,000 m3) (Whalley, 1984). The current contribution provides an approach of integral process analysis for a 200 m3 carbonate block above the federal road B 305 near the city of Salzburg in the Bavarian Alps, Germany. We performed detailed analysis of the critical carbonate block exposed to planar failure. The block volume and the dimensions of the failure surface were mapped in detail, due to the unique occasion of an accessible failure surface. The discontinuity persistence was recorded to assess a minimal degree of fragmentation for a potential failure scenario. A maximum degree of fragmentation was estimated due to recording of block dimensions at the talus slope resulting from frequent rockfalls. We performed parameter studies in terms of run-out modelling using the code RAMMS::Rockfall (Bartelt et al., 2013), taking the recorded data for block fragmentation into account. In our contribution, we aim to demonstrate a comprehensive approach for hazard assessment of mid magnitude rockfalls, taking detachment processes, fragmentation and run-out analysis into account.

Original languageEnglish
Title of host publication13th ISRM International Congress of Rock Mechanics
Editors Hassani, Hadjigeorgiou, Archibald
PublisherInternational Society for Rock Mechanics
Pages1-11
Number of pages11
ISBN (Electronic)9781926872254
StatePublished - 2015
Event13th ISRM International Congress of Rock Mechanics 2015 - Montreal, Canada
Duration: 10 May 201513 May 2015

Publication series

Name13th ISRM International Congress of Rock Mechanics
Volume2015- MAY

Conference

Conference13th ISRM International Congress of Rock Mechanics 2015
Country/TerritoryCanada
CityMontreal
Period10/05/1513/05/15

Keywords

  • 3D-run-out modelling
  • Mid-magnitude events
  • Rock falls

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