DOI: 10.5194/tc-10-2637-2016
Scopus记录号: 2-s2.0-84995426993
论文题名: Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties
作者: Schweizer J ; , Reuter B ; , Van Herwijnen A ; , Richter B ; , Gaume J
刊名: Cryosphere
ISSN: 19940416
出版年: 2016
卷: 10, 期: 6 起始页码: 2637
结束页码: 2653
语种: 英语
英文关键词: crack propagation
; data set
; elastic modulus
; instability
; mechanical property
; penetration test
; penetrometer
; quantitative analysis
; snowpack
; temporal evolution
; videography
; weather station
; Alps
; Davos
; Graubunden
; Switzerland
英文摘要: If a weak snow layer below a cohesive slab is present in the snow cover, unstable snow conditions can prevail for days or even weeks. We monitored the temporal evolution of a weak layer of faceted crystals as well as the overlaying slab layers at the location of an automatic weather station in the Steintälli field site above Davos (Eastern Swiss Alps). We focussed on the crack propagation propensity and performed propagation saw tests (PSTs) on 7 sampling days during a 2-month period from early January to early March 2015. Based on video images taken during the tests we determined the mechanical properties of the slab and the weak layer and compared them to the results derived from concurrently performed measurements of penetration resistance using the snow micro-penetrometer (SMP). The critical cut length, observed in PSTs, increased overall during the measurement period. The increase was not steady and the lowest values of critical cut length were observed around the middle of the measurement period. The relevant mechanical properties, the slab effective elastic modulus and the weak layer specific fracture, overall increased as well. However, the changes with time differed, suggesting that the critical cut length cannot be assessed by simply monitoring a single mechanical property such as slab load, slab modulus or weak layer specific fracture energy. Instead, crack propagation propensity is the result of a complex interplay between the mechanical properties of the slab and the weak layer. We then compared our field observations to newly developed metrics of snow instability related to either failure initiation or crack propagation propensity. The metrics were either derived from the SMP signal or calculated from simulated snow stratigraphy (SNOWPACK). They partially reproduced the observed temporal evolution of critical cut length and instability test scores. Whereas our unique dataset of quantitative measures of snow instability provides new insights into the complex slab-weak layer interaction, it also showed some deficiencies of the modelled metrics of instability - calling for an improved representation of the mechanical properties. © Author(s) 2016. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75046
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: WSL Institute for Snow and Avalanche Research SLF, Flüelastrasse 11, Davos Dorf, Switzerland
Recommended Citation:
Schweizer J,, Reuter B,, Van Herwijnen A,et al. Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties[J]. Cryosphere,2016-01-01,10(6)