Modeling snow slab avalanches caused by weak-layer failure – Part 2: Coupled mixed-mode criterion for skier-triggered anticracks

• Published in: The cryosphere 2020-01, Vol.14 (1), p.131-145
• Main Authors: Rosendahl, Philipp L, Weißgraeber, Philipp
• Format: Article
• Language: English
• Subjects: Avalanches; Skiers; Sports injuries
• ISSN: 1994-0424; 1994-0416; 1994-0424
• DOI: 10.5194/tc-14-131-2020

Using the analytical model presented in Part 1 of this two-part paper, a new conceptual understanding of anticrack nucleation in weak layers is proposed. To obtain a sufficient condition for onset of failure, two necessary conditions must be satisfied simultaneously: (i) the weak layer must be overloaded in terms of stress and (ii) the initiating crack must release enough energy for the formation of new surfaces. This so-called coupled criterion was proposed by Leguillon (2002). No assumptions on initial defects within the weak layer are needed. Instead, the failure criterion provides both critical loading and the size of initiating cracks. It only requires the fundamental material properties strength and fracture toughness as inputs. Crack initiation and subsequent propagation are covered by a single criterion containing both a strength-of-materials and a fracture mechanics condition.