Issue 14

B. M. Chiaia et esters (holes n from unsta olumn of ho itions of the n our simulat k tip within

alii, Frattura ed with radius ble fracture les (Figs. 4a initial crack, ions, can be the hole. Aft

Integrità Strutt equal to 3 m condition to and 4b). the simulatio estimated as er a minimu

urale, 14 (2010) ), fracture pr a stable one, ns give simi being approx m point (B),

45-51; DOI: 10 opagation in with crack a lar results: ea imately twice the K I facto

.3221/IGF-ESIS.

14.05

arr wa bet Fig cre wh unt

angement of s totally inter ween the firs . 5a and 5b s ates a “influe ich avoids th il another inf

circular or h rupted. Note t and the sec how that, va nce area” (wh e coalescenc luence area i

exagonal arr the transitio ond vertical c rying the pos ose radius, i e of the crac s reached.

the snow co rrest that oc ch crack arre the hole rad r increases a

ver curs ster ius) gain

(a) ith a quincun

(b) angement. (b)

Figure 4 : (a) C

rown fracture

propagation w

cial circular cra

ck arrester arr

Plot of K ID

v s. crack length .

(a) th a quincunci

(b) rrangement. (b

F

igure 5 : (a) Cr

own fracture p

ropagation wi

al hexagonal c

rack arrester a

) Plot of K ID

vs. crack lengt

h.

D I

SCUSSION A

ND CONCL

USION

act ava due for slab Th the the sto T

he simu that, to indepen

lations show increase spa dent avalanch protection. triggering, b propagation rtificial disco slabs, causin implementat ral arresters: he snowpack pagation ins

the effectiven tial variabilit es. So, we c Usually, the ut it is not s in the weak l ntinuities (vo g small avala ion of snow the tree slow . Moreover t ide of the w

ess of these y helps to s an suppose t long term c o infrequent ayer. Thanks id) distribute nches to pro crack arreste s the flow o he perimeter ood, the cr

arresters to r tabilize the s hat the use o ontrol struct in big slopes to the snow d along the pagate with l rs arises from f snow avala of the fores ack is heade

educe substa lope, eventu f crack arre ures for sno that fracture crack arreste snow slope a ess catastrop three in sit nches and pr t is a natural d downhill. T

ntially the cr ally splitting sters is a first w avalanches in the crow rs, we put fo rea: the targe hic effects. u observation events the re obstacle for he second

ack driving f a major ev step toward in the uppe n can bypass rward here a t is to split a s. The first lease of aval the fracture i observation

orce. This me ent into sma s a new idea r zones prev the protecti new philoso large avalan is the analysi anches thank n the snowp comes from

ans ller, for ent ons, phy che s of s to ack: the

ive avalanche lanches from to Mode II the use of a into smaller e idea of the trees as natu stability of t pping its pro

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