The energy release rate of mode II fractures in layered snow samples

Sigrist, Christian; Schweizer, Jürg; Schindler, Hans-Jakob; Dual, Jürg

doi:10.1007/s10704-006-6580-9

Cited by 17 publications

(28 citation statements)

References 21 publications

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“…The mean critical energy release rate of G c = 0.07 ± 0.02 J m −2 that was found for the tested weak layer on 27 January 2006, is comparable to the critical energy release rate found in previous laboratory experiments ( G c = 0.04 ± 0.02 J m −2 ) [ Sigrist et al , 2006]. Compared to critical energy release rates for interfaces such as ice‐aluminum ( G c = 1 J m −2 ) or ice‐steel ( G c = 5 J m −2 ) [ Wei et al , 1996], the above values for weak snowpack layers are extremely low.…”

Section: Discussionsupporting

confidence: 88%

Critical energy release rates of weak snowpack layers determined in field experiments

Sigrist¹,

Schweizer²

2007

Geophysical Research Letters

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[1] A field experiment was developed to measure the critical energy release rate for fracture propagation in a weak snowpack layer. A snow block was isolated on a slope and tested in-situ by cutting along the weak layer. Critical cut lengths of about 25 cm were required to start fracture propagation along the weak layer. The critical energy release rate was determined numerically from the critical cut length with a finite element simulation. The mean critical energy release rate for the tested weak layers was about 70 mJ m À2. Numerical simulations showed that slope normal bending of the slab, in addition to the slope parallel shear deformation, contributed considerably to the energy release rate in our experimental setup. Citation: Sigrist, C., and J. Schweizer (2007), Critical energy release rates of weak snowpack layers determined in field experiments, Geophys. Res. Lett., 34, L03502,

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Section: Discussionsupporting

confidence: 88%

Critical energy release rates of weak snowpack layers determined in field experiments

Sigrist¹,

Schweizer²

2007

Geophysical Research Letters

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“…The snow characteristics for this case were: ρ H = 76 kgm −2 , D /ρ H = 70 m 4 s −2 and h ≅ 1.5 mm. Typical fracture energies w f for weak snow layers are not yet precisely known but are assumed of the order of 0.01 to 1.0 Jm −2 [ van Herwjinen , 2005; Sigrist et al , 2006] or higher for stronger layers.…”

Section: Discussionmentioning

confidence: 99%

An analytical model for fracture nucleation in collapsible stratifications

Heierli

Zaiser

2006

Geophysical Research Letters

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In collapsible stratifications a particular type of fracture can develop for which nucleation and propagation are governed by the transformation of gravitational energy into fracture energy. The associated nucleation problem is studied for a stratification consisting of an elastic surface layer, a collapsible intermediate layer and a rigid basal layer. An analytical model for fracture nucleation is obtained by calculating the energy ('crack energy') associated with a localized collapse of the intermediate layer. The size and energy of a critical crack are evaluated as functions of continuum properties of the strata. The theory is illustrated by an application to the case of whumpfs in collapsible snow stratifications. Citation: Heierli, J., and M. Zaiser

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“…No external force is necessary to reduce the avalanche velocity (see section 5 examples). Furthermore, we do not consider the momentum change caused by fracturing the snow cover as the fracture energy in new snow is small [ Sigrist et al , 2006].…”

Section: Model Equationsmentioning

confidence: 99%

Modeling mass‐dependent flow regime transitions to predict the stopping and depositional behavior of snow avalanches

Bartelt¹,

Bühler²,

Buser³

et al. 2012

J. Geophys. Res.

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.[1] How terrain, snow cover properties, and release conditions combine to determine avalanche speed and runout remains the central problem in avalanche science. Here we report on efforts to understand how surface roughness, snow properties, and internal mass fluxes control the generation of granular fluctuation energy within the basal shear layers of dense flowing snow avalanches, and the subsequent influence on avalanche speed and deposition patterns. For this purpose we augment the depth-averaged equations of motion to account for the generation of the kinetic energy associated with the particle fluctuations, and dissipation of this energy by collisional and frictional material interactions. Using high-resolution laser scans of the preevent snow cover and postevent deposits from two avalanches released at the Swiss Vallée de la Sionne observation station, we compare measured and calculated deposition heights. The model captures flow velocities and deposition heights without ad hoc adjustments of the constitutive parameters according to avalanche size. The model parameters are separated into a terrain and other pure material (snow) parameters. The investigations reveal how release conditions and snow entrainment influence the internal mass distribution, and control flow regime transitions between the fluidized regime (head) and plug regime (tail). The comparison between the measured and calculated velocities and deposition heights demonstrates why standard Voellmy-type submodels are suitable for many practical mitigation problems, but also why they are limited to cases where the calibrated parameters, already accounting for terrain, snow cover properties, avalanche size, and mass intake, are known.

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The energy release rate of mode II fractures in layered snow samples

Cited by 17 publications

References 21 publications

Critical energy release rates of weak snowpack layers determined in field experiments

Critical energy release rates of weak snowpack layers determined in field experiments

An analytical model for fracture nucleation in collapsible stratifications

Modeling mass‐dependent flow regime transitions to predict the stopping and depositional behavior of snow avalanches

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