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DOI	10.5194/tc-10-2637-2016
	Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties
	Schweizer J.; Reuter B.; Van Herwijnen A.; Richter B.; Gaume J.
发表日期	2016
ISSN	19940416
卷号	10 期号:6
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.
学科领域	crack propagation; data set; elastic modulus; instability; mechanical property; penetration test; penetrometer; quantitative analysis; snowpack; temporal evolution; videography; weather station; Alps; Davos; Graubunden; Switzerland
语种	英语
scopus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
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119551
作者单位	WSL Institute for Snow and Avalanche Research SLF, Flüelastrasse 11, Davos Dorf, 7260, Switzerland
推荐引用方式 GB/T 7714	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],2016,10(6).
APA	Schweizer J.,Reuter B.,Van Herwijnen A.,Richter B.,&Gaume J..(2016).Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties.Cryosphere,10(6).
MLA	Schweizer J.,et al."Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties".Cryosphere 10.6(2016).