Rockfall characterisation and structural protection – a review

Volkwein, Axel; Schellenberg, Kristian; Labiouse, V.; Agliardi, Federico; Berger, Frédéric; Bourrier, Frank; Dorren, Luuk; Gerber, Werner; Jaboyedoff, Michel

doi:10.5194/nhess-11-2617-2011

Cited by 375 publications

(263 citation statements)

References 137 publications

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“…Direct observation of events is rare and restricted to, for example, the Yosemite Valley, with thousands of cameraequipped tourists per day (Stock et al, 2013). Typical approaches to deliver information about rockfalls are deterministic and probabilistic susceptibility analysis, predictive modelling, a posteriori mapping of detachment zones, released volumes and pathways by aerial and satellite imagery or repeated terrestrial laser scan (TLS) surveying (Volkwein et al, 2011). The last of these techniques (Ring, 1963) provides high-resolution spatial data of topographic change attributable to rock detachment (e.g.…”

Section: Introductionmentioning

confidence: 99%

Seismic monitoring of small alpine rockfalls – validity, precision and limitations

Dietze

Mohadjer²,

Turowski

et al. 2017

Earth Surf. Dynam.

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Abstract. Rockfall in deglaciated mountain valleys is perhaps the most important post-glacial geomorphic process for determining the rates and patterns of valley wall erosion. Furthermore, rockfall poses a significant hazard to inhabitants and motivates monitoring efforts in populated areas. Traditional rockfall detection methods, such as aerial photography and terrestrial laser scanning (TLS) data evaluation, provide constraints on the location and released volume of rock but have limitations due to significant time lags or integration times between surveys, and deliver limited information on rockfall triggering mechanisms and the dynamics of individual events. Environmental seismology, the study of seismic signals emitted by processes at the Earth's surface, provides a complementary solution to these shortcomings. However, this approach is predominantly limited by the strength of the signals emitted by a source and their transformation and attenuation towards receivers. To test the ability of seismic methods to identify and locate small rockfalls, and to characterise their dynamics, we surveyed a 2.16 km 2 large, near-vertical cliff section of the Lauterbrunnen Valley in the Swiss Alps with a TLS device and six broadband seismometers. During 37 days in autumn 2014, 10 TLS-detected rockfalls with volumes ranging from 0.053 ± 0.004 to 2.338 ± 0.085 m 3 were independently detected and located by the seismic approach, with a deviation of 81 +59 −29 m (about 7 % of the average inter-station distance of the seismometer network). Further potential rockfalls were detected outside the TLS-surveyed cliff area. The onset of individual events can be determined within a few milliseconds, and their dynamics can be resolved into distinct phases, such as detachment, free fall, intermittent impact, fragmentation, arrival at the talus slope and subsequent slope activity. The small rockfall volumes in this area require significant supervision during data processing: 2175 initially picked potential events reduced to 511 potential events after applying automatic rejection criteria. The 511 events needed to be inspected manually to reveal 19 short earthquakes and 37 potential rockfalls, including the 10 TLS-detected events. Rockfall volume does not show a relationship with released seismic energy or peak amplitude at this spatial scale due to the dominance of other, process-inherent factors, such as fall height, degree of fragmentation, and subsequent talus slope activity. The combination of TLS and environmental seismology provides, despite the significant amount of manual data processing, a detailed validation of seismic detection of small volume rockfalls, and revealed unprecedented temporal, spatial and geometric details about rockfalls in steep mountainous terrain.Published by Copernicus Publications on behalf of the European Geosciences Union.

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Section: Introductionmentioning

confidence: 99%

Seismic monitoring of small alpine rockfalls – validity, precision and limitations

Dietze

Mohadjer²,

Turowski

et al. 2017

Earth Surf. Dynam.

View full text Add to dashboard Cite

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“…Some models consider a combination of both approximations at different stages of the calculation process (hybrid approach). Examples of models using these different approaches are shown in Volkwein et al (2011).…”

Section: -Block Shapementioning

confidence: 99%

“…A compilation of the common practices in rockfall numerical modelling and a classification of the existing models is found in Volkwein et al (2011). More recently, in the field of rockfall propagation modelling, Gischig et al (2015) proposed a new 3D model that includes a different methodology that considers hyperbolic restitution factors.…”

Section: -Block Shapementioning

confidence: 99%

“…In lumped mass models the block rebound is usually defined by normal Rn and tangential Rt restitution coefficients (Equation 3) that describe the decrease in the normal and tangential velocities after impact (Volkwein et al, 2011).…”

Section: Impact and Rebound Modelmentioning

confidence: 99%

“…Many rockfall analyses are oriented to the assessment of the damage caused to people, civil infrastructures and buildings as well as to the proper design of mitigation measures. Extended reviews of qualitative and quantitative methodologies for rockfall hazard assessment can be found at Volkwein et al (2011) and Ferrari et al (2016).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

RockGIS: a GIS-based model for the analysis of fragmentation in rockfalls

et al. 2017

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ABSTRACT:A Rockfall is a mass instability event frequently observed in road cuts, open pit mines and quarries, steep slopes and cliffs. After its detachment, the rock mass may disaggregate and break due to the impact with the ground surface, thus producing new rock fragments. The consideration of the fragmentation of the rockfall mass is critical for the calculation of the trajectories of the blocks and the impact energies, for the assessment of the potential damage and the design of protective structures. In this paper, we present RockGIS, a GIS-Based tool that simulates stochastically the fragmentation of the rockfall, based on a lumped mass approach. In RockGIS, the fragmentation is triggered by the disaggregation of the detached rock mass through the pre-existing discontinuities just before the impact with the ground. An energy threshold is defined in order to determine whether the impacting blocks break or not. The distribution of the initial mass between a set of newly generated rock fragments is carried out stochastically following a power law. The trajectories of the new rock fragments are distributed within a cone. The fragmentation model has been calibrated and tested with a 10,000m 3 rockfall that took place in 2011 near Vilanova de Banat, Eastern Pyrenees, Spain.

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Massenbewegungen

Genske¹

2017

Grundbau‐taschenbuch

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Rockfall characterisation and structural protection – a review

Cited by 375 publications

References 137 publications

Seismic monitoring of small alpine rockfalls – validity, precision and limitations

Seismic monitoring of small alpine rockfalls – validity, precision and limitations

RockGIS: a GIS-based model for the analysis of fragmentation in rockfalls

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