Numerical approach to predicting stresses and displacements around a three-dimensional pressurized fracture

22A

ere carried out fc~ both area amd llne samplAmg a~d Cover the di~tA~Abut~ons cf trace l ~ a~i spaclm@~, Imnludlz~ allc~ance for trumcatlon. An a~ml.leatlon to rock bol~Img is alsO d e s c r i b e d . The equetlC~s are cox~verted, where ~ e s s a r ~ to forms ~hat facillta~e z,w~ical evaluation. An example illustrates hov t h e p a r a m e t e r s o f the medel ms7 Be obtained frc~ field data. Auth.

Fracture processes 812009 FRACTURE STRESS SCALE EFFECTS FOR ROCKS IN BENDING Swan, G Int J RCC.M Mech M~n Scl, VI7, ~ , Dec I~0, P317-32~ T h e n a t u r e c~ f r a c t u r e e t r e s s a i z e d e l ~ i e n c y is examined fcr rocks in benli~g. After establlahi~ the ~rder of ~he depeniemcy for unnotched s~eclmens, notched specimens ere then used so facilltatlr~ a fracture mechanics ~pproach. Such an approach Is fcmmd to better q u a n t i f y fracture stress scale effects than the alternative a ~ o a c h of Velbull-~Lv~e s~at~atlcal arguments. The explanation fc~ this is found t o lie in the teaser's abl~Ity t o t a k e i n t o account st~-erltleal crack ~rcw~h effects ~ricr to the ~racture stress event in rocks. Auth.

812010 ~ R ~ C A L AI~OACH TO P R ~ Z C T X ~ STRESSES AND DZSPLACEMENTS AROUND A THREE-DIMENSZONAL PRESSURIZED H:'~, O; Murge~stern, N R Int J Rock M ~ h Min SC1, VI7, N6, Dec 1960, PS33-338 A numerlce~ t e c h n i q u e h a s been d e v e l o p e d far ~ l y s l s of stresses end dlsplace~ents arotu~ a l~ess~rized Dl~mar fracture of arbitrary ge~metA~y I n three ~t=e~stons. The a m l y s l s l s limited by a s ~ of hcm0~eaeit¥ ~ linear elasticity, but it is eapshle of eonslderlm~ the effects of arbl~rary Internal I~esetwe dls~-Xbution, ~ tangential in~tlal stresses, a~i the ~esence c~ a ~ree s~U~ace. The l~eaent a~llcatic~ C~ t ~ e ~ c h n l q u e h a s b e e n c r i e ~ a ~ e d towards the determi~atlom of far-fleld coni~tions ra~her ~ stress e c ~ c ~ I c ~ s . Sample a o l u tlons are Irese~t~d, I n e l ~ l ~ a d e ~ n a ~ r e t t o n of the In~l~emee c~ f r a c t u r e c r l e n ~ i o n a~d initial s~ess state upon free surface uplift. 812011 SLOW CRACK GROWTH AND DELAYED FAZE~RE OF Wilkins, B J S X ~ • Rock Mech Min Scl, V17, N~, Dec 1 ~ 0 , Dela~ei f a i l u r e of ~ r s ~ I t e was measured a t v a l u e s e f constant app~ed a ~ r e s s . A~ a ~ a l y s l s was develo]~d ~.o d s t w ~ n e f r o m t h e s e d a t a the rate cf g r c ~ h of 1~a-e~Is~i~ cracks. T h e r e s u l t s a r e ex~cessed i n t e r m s c~ c r a c k - ~ r o ~ t h veloelty as a f~mctlcm of the a~ress l ~ u ~ I t y fac1~. The ~ h n l q u e is = a l m b l e c~ d e t e c t i n g crack-~rc~th velocities as IC~ as (i0 tO ~b.e

z:.~ver -12) m/s. 812012 F R A C T ~

M~CNA~NCS P

~

OF SCME ROCK-

~ b ~ ~ AN r I ~ T A T X O N ~'~CI~NX~JE. "rEu~iCAL NOTE A ~ k i ~ n , B K; Av~Is~ V Int J Rock Mesh MAn SOl, ~F~7, N6, Dee i~O,

~3"~

Reports measurement cf the fracture surface em~ of calclte, galena, ~yrlte, synthetic quartz, syuthetic spinel, feldspar ar~ soda llme glass, and derivation of the critical strain energy release rate ani the critical stress intensity factor. 812013 FACTORS AFFECTI~ THE ACOUSTIC E.rISSION .RESPONSE OF TRIAXIALLY COMPRESSED ROCK Goal, T N Int J Rock Me~Ca Min Sci, VlT, N~, Aug 1980, P219-223 To investigate the mechanism of brittle fract~e, investigations ware married otrt on aco~M~ic e m i s s i o n s f r o m ~ u n t a a ~ d s t o n e sl~mime~s = c ~ e n e d trlaxlally at : o m f l n i ~ g ~resstwes ra~gi~ from atmospherlc ~resa~e to the ~rittle-ductlle t r a n s i t i o n ~ressure. The acoustle emissions were monitored in the frequency band of i00300 kHz a~i over the complete rmmge of s ~ - c i men defcrma~ion Includl~ t h e post-failure re.on. 8120!% .~e'~CT OF CONFINinG PRESSURE ON THE FRACTUEE B~AV~OUR OF A POROUS ROCK Go,i, T N; R~mmel, F I ~ J Rock Mech Min Scl. V!7, N&, Aug 1980,

P22p-229 TriaxisA ceml~e~lon tests were carried out on a p o r o u s s a n d s t o n e f r o m S~ Germar~. The c o ~ l n img PressUres ranged up to 200 MPa. Direct volumetric strain measurements Inlic~ted that ~e-peak mlcrofracturimg l s a ~ecurs~ry defc~atiOn l~ocess to the development of macros c o p i c shear faults in I n ~ t porous rock at lov confining l ~ e s ~ e s . Po~t-peak dilation at low ~resst~es As ~ue to fault dilation. At high ~ e s s t w e s multiple shear frmct~res d e v e l o p w i t h pro~resslvely less dilation. ~anslt~on from bridle to ductile d e f ~ i ~ n takes place at a conflnlmg ~ e s ~ e of IO0 MPa. Ductile shear at ~ ~ressure occurs w'Ith~Ut a=y dilation, a~d leads to l~o~rees~ve cc~l~e~ion and homogeneous sheer t~-ou~hou~ the rock specimen.

812015 STRESS I~I~NSITY FACTOR COMPUTATION IN T~REE DIMENSIONS WITH ~ z ~ - P O I N T ~ S I~graffea, A R; Mane, C Int J Nt~ Meth Engmg, V15, ~&O, Oct i~80, The method is ~resented a~i gexmre.1~aed to permlt ftu~tlomal eval~at~on c~ streas-intenalty factc~s alomg the crack front. Embedded, am'face ani c c r ~ crack problems are Belved a anl results compared vlth IreVlOUS finite element amd b~Imdary element solutioms. A Beam f ~ e co~atlon b e i ~ used by the a~thars to study ~ a ~ t ~ e p r o p ~ i o m in rock is evaluated by the ~ o p o N d method.

Strength characteristics 812016 F ~

OF ~ Y ISOTROPIC ROCKS IN TRIAXZAL COMPRESSION Nova, R Int J Rock Mesh Mira Sel, VI7, N6, Dec 1980,

~2~-332 The thec~stlcal ~redlctions obtaAmed free a recently developed theory of the failure condltions fc~ crthetro~C solids are compared with ex~rimental results on the faille of