Issue 14

B. M. Chiaia et

alii, Frattura ed

Integrità Strutt

urale, 14 (2010)

45-51; DOI: 10

.3221/IGF-ESIS.

14.05

N

umeric

al study

of frac

ture arr

est on

snow co

ver

B. Pol Co bar

M. Chiaia itecnico di Tor rso Duca degli bara.frigo@p

, B. Frigo ino, Departm Abruzzi, 24 olito.it

ent of Structu , 10129 Tor

ral and Geote ino, Italy

chnical Engin

eering,

STRACT . U merically by rinsically dy er, we mod ck propaga suming that est fracture ilosophy for tributed alo lanches to p YWORDS . F

nder the hy means of L namical, an el dynamic tion throug the weak l propagation the use of ng the snow ropagate w racture mec y the snow a thick, stro isms: it start ), fracture at perfectly bri Mechanics presented by hanism of dr de II fractur s a numerica crack arreste is considered ing into acco e propagatio spatial varia ts spatial vari pproaches, s s lower pro possible redu N

pothesis of inear Elast other aspec crack propa h the prese ayer is almo , into the fr artificial di slope area: ith less cata hanics; Sno stratifications ng and stiff s with fractu the flanks ttle phenome [1, 2]. Since dynamic fra y slab avalan e propagation l simulations rs. like a linear unt kinetic e n and their s bility of the ability would uch as cellu bability for ction of the

a perfectly ic Fracture t to investi gation into nce of wea st collapse amework o scontinuities the target is strophic effe w avalanche , the snowp slab and coh re at the we (Mode II an non, avalanc , however, t cture propag ches trigging between we to analyse it –elastic plat nergy and th tability have b physical and lead to lowe lar automata catastrophic propagation

omenon, av (LEFM). Sin esented by slab and we tributed alo ate the effic l Fracture M the snowp rge avalanch

alanche trig ce, howeve dynamic fra investigate ng the exte iency of ar echanics. W ack able to e slab into

gering can r, the real p cture propa the possibil nsion of th tificial voids e put forw perform as smaller slab

be investiga henomeno gation. In ity to arrest e snow slo in the slab ard here a n crack arres s, causing sm

ted n is this the pe. to ew ters all

brittle phen Mechanics gate is repr a dry snow k zones dis d, we simul f Dynamica (void) into to split a la cts. ; Crack arre ack can be s esive basal la ak layer on t d Mode III) he triggering he real phen ation. In the : the fracture ak layer and s possible ar e (2D proble anks to the u een investig mechanical p r release prob [4] and sta avalanches of crown fr

A B nu int pap cra As arr ph dis ava

sters; Active

protection .

K E

I N

TRODUCTIO

C

aused b between mechan

chematized a yer. The slab he bed surfa and fracture is usually inv omenon is framework o at the crow snow slab), t rest based on m) with phy se of the FE ated in contin roperties of ability for sn tistical mech is the same acture by the

s a sandwich avalanche r ce (Mode II) at the stau estigated nu intrinsically d f Fracture M n. As a conse he secondary Dynamic El sical parame M software uous (natura snow cover, ow avalanch anics [5] mo . To suppor theory of C

structure: a elease pursui following b chwall (crush merically by ynamical, an echanics, th quence of th Mode I crac astic Fractur ters chosen FRANC 2D l) snow cove some studie es. Although dels, the ide t this percep rack Arrester

thin weak l ts a sequenc y fracture at ing). Under means of Lin other aspec e paper anal e first trigge k propagatio e Mechanics according to [3], several p r. s have sugge the studies h a that increa tion, the pa s applied on

ayer e of the

the ear

cro hyp Ela inv the me stu on Th lite of Co tha ver var inv

wn (Mode I othesis of a stic Fracture estigate is re second mec chanism (Mo died by mean the theory of e snowpack rature. By tak crown fractur nsidering the t increasing i y different a iability cause estigates the

t to yses ring n is and the aths sted ave sed per the

45