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Modelling of rock reinforcement systems in cut and fill mining
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620 LACK,LJ HYDRO-ELECT.~ . T A S M A N I A , AUS BOWLI~I~,AJ HYDR0-ELECT. ~ . T A S M A N I A , AUS KNOOP, BP HYDRO-ELECT.~ . T A ~ W A N I A , AUS Rock mechanics a t e : l i e s a n l i n s ~ n t a t i o n for ~he C~rdon urdargroumd Ix~ar station. 3F,1T,TR. 2ND AUS-N.Z.CONF.GE~,~ISBANE~1~75~ INST.ENGRS, AUS.NAT.CONF.~ . NO.75/~, P27~-280. The Gordon ur¢lergroumd power s t a t i o n i s the only germrating facility in the Gordon Rive¢ Power Development Stage 1. The powar station is approximately 200m umd.argrou~i ard Is situated in follated quartzite and schist. I n c r d a r %0 provide d e s i g n d a t a on r o c k ~reparties and to ~oni~ t h e b e h a v i o ~ o f t h e u ~ a r g r o t m d w ~ k s both d u r i ~ a~d a f t e r construction a comprehensive l~o~ramme of rock testing a ~ structural behaviour instrumentation has been unlartaken. The paper describes the rock t e s t i n g p r o c e d u r e s which have b e e n u s e d ar~ t h e r e s u l t s o b ~ i ~ e d , ar~ t h e d e s i g n o f t h e v a r i o u s t y p e s o f perman e n t i n s t r ~ n e n t s ar~ t h e i n s ~ n ~ n e n t a t i o n systam. Auth.
In-situ stresses and stress around underground openings 621 WOROTNICKI,G ~ ~ , LG A ~ C R O F % JF D e f o r m a t i o n and behaviour of h i g h rise filled s t o p e s a% C.S.A. mine, Cobar, N.S.W. 12F~2T,2~R. 2N~ AUS-N.Z.CONF.GEC~,~RISBA~l~75, INST.E~RS, AUS .NAT.CONF.PUSL.NO.75/~,I:~8-55. Measurements at Cobar C.S.A. Mine (N.S.W.) were made of stresses ar~ defo~=~=tic~s in the backs and walls of main stopes a~d in the stops fill %0 assess the safe~r of b a c k s ami walls, ar~ %0 study %he b e h a v i o u r o f the r o c k mass. The o b s e r v a t i o n s a r e c c e ~ r e d w i t h p r e d i c t i o n s f o r elastic intact homogeneous material, and the similarities with ard d e p e r t a r e s from the ~edlctloms are d/scussed. Some uew inslz~P.nts were developed for the det e r m i n s t t o n o f p r e - m i n i n g stresses, for o b s e r v a t i o n s of strain in the rock a~l settlement of fill. Auth.
622 ALEXAND~, LG FRASER,CJ Expariemces in the meam~ement of rock dilation with three-depth, red-t~pe, borehole extenscmeters. 2ND AUS-N.Z.CONFERE.GEC~ECH,~qISBANE,1975,I N ~ .E~GRS,
AUS.~AT.CO~F.~JSL.NO.?~/~,~8~-286. ~ree-depth red-type ~rehole extenscmetars are used to measure rock dilations in the rock sln'round o f advancir6 tunnels, commencing within 0.3 m of the face ar~, initially, giving the dilation caused by stress to~a~ blasting add e x t ~ n g to time effects ~p days. From results obtained add ~he measured l~ry rock s t r e s s e s , a d e f o r m a t i o n n~xlulus was d e r i v e d f o r one project@ f o r s t r e s e - d o f c ~ a t i o n s t u d i e s of a large excavation. For anot~ar project an alternative a p ' ~ o a c h was used. The excess dilation (dilation due t o c r a c k opening a~d creep) was c a l c u l a t e d f o r t h e d e s ~ n o f a p r e s s t ~ e t u n n e l l i n i n g : Auth.
Surface subsidence and caving 623 WOOD,CC RENFREY,GJ The influence of miniDg st~eider~ce on urban developmerit of Ipswich, Queemslmmd. 3F, IT,17R. PROC.2ND AUS-N.Z.CONF.ON GE C ~ I S B A N E ~ I ~ 5 , INST. EI~RS,AUS, NRP.CONF.PUB.NO.75/~,P~'9. Urban develol~nent at I p s w i c h in s o u t h e r n Queensland i s exter~llr~ into areas where extensive uDdar~round coal
mining operations have been carried out for more than a century. An assessment of mining s u b s i d ~ e potential was undertaken %0 help rationsllse future town Plan~Ing of Ipewlch City. Mimir~ in the area has ~ ' a ~ I t i o m l ly b e e n b y "b~m~l and. p i l l a r " methods w i t h p i l l a r e x t r a c t i o n in the latter stages of minir~ whare cor~tlons permit; Predictable s ~ s t d e ~ c e o f "the ground s u r f a c e occurs following pillar extraction. However~ surface movements resultlr~ from d e t e r i o r a t i o n o f o l d mine wc~klr~s are not amenable to exact celculstion and a classification scheme involvir~ six "St~slden~e Categories" has been evolved for g e n e r a l plannIDg purposes. Infc~-ration frcm mine plans amd various other sources was assembled a s overlays on a e a d a s t r s l b a s e map o f ~he City area. The area was classified accc~dlng %0 degree of risk of surface defc~matlon~ am~ overlays imeluded locations of operating ard abandoned collieries, identification of coal miming leases, ir~Livldual seam workings ar~ features of geological i m ~ e . Construction restrictions and design requirements were defined for the various categories ar~ the ~ature of follow-up studies for proposed develop6ents was specified. Auth.
Temporary and permanent supports 624 MATHEWS,KE UNIV.~IT. COLUM.CDN MEEK,JL UNIV. Qt~q~SIAND,AUS Mode11~r~ of rock reinforcement systems in cut fill mining. ~Fa2T,TR. 2ND AUS- N.Z.CONF.G ~ , BRISBANE,1975,INST .E~RS, AUS.NAT.CONF.PUBL.NO.75/4,~2-47. The procedures c u r r ~ used. for the design of rock reinforcement in fractured strata 8re reviewed briefly. The trer~ to install support systems u s l ~ full column resin c~ grouted dowels as opposed ~o poim¢ ~ h o r e d bolts, is discussed a ~ the results of investigations carried out are reviewed in context with design obJectives associated with cut a ~ fill minlng l~ogresses. Examples a r e given %0 Illustrate the Ir~lems encountered amd the procedures deweloped %0 resolve them. Future developments leadimg %0 im~ove~ deslgn of reinforcemen~ systems in f r a ~ u r e d strata ere postulatei ar~ topics w c ~ of e o ~ i n u i z ~ research a~d develolxnent activity are discussed. Auth.
625 IO~)YBINSKI,A The influence of i o ~ I stlplx~ beariDg cal~acity on the distribution of stresses anl zones of failure in the roof rocks. In Polish. P ~ C E GLO~.LWSnGO~.~55,1975,P3-36. T e s t s were c a r r i e d o u t on a ~ d a l o f a l o ~ a l l r.1~ systeTM c o m ~ i s i ~ inlividual props of constant bearing capacity a ~ a r t i c u l a t e d s t eel roof ]~ars set l~rpendlcularly %0 the face. The distribution of stresses, the safety factor, and the 1~n~ast pressuce sufficien~ %0 destroy the roof were determlmd. Fez tZplcal roofs of ala~e7 shales ~his critical p r e s ~ e was shout 80-~0 ~ f o r o~e imiivldual prop. For mecBanized a~pport, critical stresses are about half the usual values, amd the critical presmce on the roof depemis on the actual c o n t ~ area. Tests showed that to iml~ove roof stability the level of h~rizental %0nails stresses on ~he s~face of ~he ~ of t h e worki~s must be reduced. To achieve this, t h e diatribution of nominal b e a r i ~ capacity must be modified, ezd a ~stantlal Inarease in p r - l ~ - ~ s ~ bearlx~ capacity relative %0 wcad~.~ eapaclty i s Decessary. The co~Li~ions could be s~isfied if shield ~ype s u l ~ s were used.Auth.
626 KO~OPA,W S~e~@~h and beariDg capacity of an iDilvidual h~ullc prop under static loading assessed from c a l c u l a t i o n s a ~ s t u d i e s on a t o s t r i g . In P o l i s h . A d e s c r i p t i o n i s g i v e n o f a method o f c a l c u l a t i o r ~ t h e
620 LACK,LJ HYDRO-ELECT.~ . T A S M A N I A , AUS BOWLI~I~,AJ HYDR0-ELECT. ~ . T A S M A N I A , AUS KNOOP, BP HYDRO-ELECT.~ . T A ~ W A N I A , AUS Rock mechanics a t e : l i e s a n l i n s ~ n t a t i o n for ~he C~rdon urdargroumd Ix~ar station. 3F,1T,TR. 2ND AUS-N.Z.CONF.GE~,~ISBANE~1~75~ INST.ENGRS, AUS.NAT.CONF.~ . NO.75/~, P27~-280. The Gordon ur¢lergroumd power s t a t i o n i s the only germrating facility in the Gordon Rive¢ Power Development Stage 1. The powar station is approximately 200m umd.argrou~i ard Is situated in follated quartzite and schist. I n c r d a r %0 provide d e s i g n d a t a on r o c k ~reparties and to ~oni~ t h e b e h a v i o ~ o f t h e u ~ a r g r o t m d w ~ k s both d u r i ~ a~d a f t e r construction a comprehensive l~o~ramme of rock testing a ~ structural behaviour instrumentation has been unlartaken. The paper describes the rock t e s t i n g p r o c e d u r e s which have b e e n u s e d ar~ t h e r e s u l t s o b ~ i ~ e d , ar~ t h e d e s i g n o f t h e v a r i o u s t y p e s o f perman e n t i n s t r ~ n e n t s ar~ t h e i n s ~ n ~ n e n t a t i o n systam. Auth.
In-situ stresses and stress around underground openings 621 WOROTNICKI,G ~ ~ , LG A ~ C R O F % JF D e f o r m a t i o n and behaviour of h i g h rise filled s t o p e s a% C.S.A. mine, Cobar, N.S.W. 12F~2T,2~R. 2N~ AUS-N.Z.CONF.GEC~,~RISBA~l~75, INST.E~RS, AUS .NAT.CONF.PUSL.NO.75/~,I:~8-55. Measurements at Cobar C.S.A. Mine (N.S.W.) were made of stresses ar~ defo~=~=tic~s in the backs and walls of main stopes a~d in the stops fill %0 assess the safe~r of b a c k s ami walls, ar~ %0 study %he b e h a v i o u r o f the r o c k mass. The o b s e r v a t i o n s a r e c c e ~ r e d w i t h p r e d i c t i o n s f o r elastic intact homogeneous material, and the similarities with ard d e p e r t a r e s from the ~edlctloms are d/scussed. Some uew inslz~P.nts were developed for the det e r m i n s t t o n o f p r e - m i n i n g stresses, for o b s e r v a t i o n s of strain in the rock a~l settlement of fill. Auth.
622 ALEXAND~, LG FRASER,CJ Expariemces in the meam~ement of rock dilation with three-depth, red-t~pe, borehole extenscmeters. 2ND AUS-N.Z.CONFERE.GEC~ECH,~qISBANE,1975,I N ~ .E~GRS,
AUS.~AT.CO~F.~JSL.NO.?~/~,~8~-286. ~ree-depth red-type ~rehole extenscmetars are used to measure rock dilations in the rock sln'round o f advancir6 tunnels, commencing within 0.3 m of the face ar~, initially, giving the dilation caused by stress to~a~ blasting add e x t ~ n g to time effects ~p days. From results obtained add ~he measured l~ry rock s t r e s s e s , a d e f o r m a t i o n n~xlulus was d e r i v e d f o r one project@ f o r s t r e s e - d o f c ~ a t i o n s t u d i e s of a large excavation. For anot~ar project an alternative a p ' ~ o a c h was used. The excess dilation (dilation due t o c r a c k opening a~d creep) was c a l c u l a t e d f o r t h e d e s ~ n o f a p r e s s t ~ e t u n n e l l i n i n g : Auth.
Surface subsidence and caving 623 WOOD,CC RENFREY,GJ The influence of miniDg st~eider~ce on urban developmerit of Ipswich, Queemslmmd. 3F, IT,17R. PROC.2ND AUS-N.Z.CONF.ON GE C ~ I S B A N E ~ I ~ 5 , INST. EI~RS,AUS, NRP.CONF.PUB.NO.75/~,P~'9. Urban develol~nent at I p s w i c h in s o u t h e r n Queensland i s exter~llr~ into areas where extensive uDdar~round coal
mining operations have been carried out for more than a century. An assessment of mining s u b s i d ~ e potential was undertaken %0 help rationsllse future town Plan~Ing of Ipewlch City. Mimir~ in the area has ~ ' a ~ I t i o m l ly b e e n b y "b~m~l and. p i l l a r " methods w i t h p i l l a r e x t r a c t i o n in the latter stages of minir~ whare cor~tlons permit; Predictable s ~ s t d e ~ c e o f "the ground s u r f a c e occurs following pillar extraction. However~ surface movements resultlr~ from d e t e r i o r a t i o n o f o l d mine wc~klr~s are not amenable to exact celculstion and a classification scheme involvir~ six "St~slden~e Categories" has been evolved for g e n e r a l plannIDg purposes. Infc~-ration frcm mine plans amd various other sources was assembled a s overlays on a e a d a s t r s l b a s e map o f ~he City area. The area was classified accc~dlng %0 degree of risk of surface defc~matlon~ am~ overlays imeluded locations of operating ard abandoned collieries, identification of coal miming leases, ir~Livldual seam workings ar~ features of geological i m ~ e . Construction restrictions and design requirements were defined for the various categories ar~ the ~ature of follow-up studies for proposed develop6ents was specified. Auth.
Temporary and permanent supports 624 MATHEWS,KE UNIV.~IT. COLUM.CDN MEEK,JL UNIV. Qt~q~SIAND,AUS Mode11~r~ of rock reinforcement systems in cut fill mining. ~Fa2T,TR. 2ND AUS- N.Z.CONF.G ~ , BRISBANE,1975,INST .E~RS, AUS.NAT.CONF.PUBL.NO.75/4,~2-47. The procedures c u r r ~ used. for the design of rock reinforcement in fractured strata 8re reviewed briefly. The trer~ to install support systems u s l ~ full column resin c~ grouted dowels as opposed ~o poim¢ ~ h o r e d bolts, is discussed a ~ the results of investigations carried out are reviewed in context with design obJectives associated with cut a ~ fill minlng l~ogresses. Examples a r e given %0 Illustrate the Ir~lems encountered amd the procedures deweloped %0 resolve them. Future developments leadimg %0 im~ove~ deslgn of reinforcemen~ systems in f r a ~ u r e d strata ere postulatei ar~ topics w c ~ of e o ~ i n u i z ~ research a~d develolxnent activity are discussed. Auth.
625 IO~)YBINSKI,A The influence of i o ~ I stlplx~ beariDg cal~acity on the distribution of stresses anl zones of failure in the roof rocks. In Polish. P ~ C E GLO~.LWSnGO~.~55,1975,P3-36. T e s t s were c a r r i e d o u t on a ~ d a l o f a l o ~ a l l r.1~ systeTM c o m ~ i s i ~ inlividual props of constant bearing capacity a ~ a r t i c u l a t e d s t eel roof ]~ars set l~rpendlcularly %0 the face. The distribution of stresses, the safety factor, and the 1~n~ast pressuce sufficien~ %0 destroy the roof were determlmd. Fez tZplcal roofs of ala~e7 shales ~his critical p r e s ~ e was shout 80-~0 ~ f o r o~e imiivldual prop. For mecBanized a~pport, critical stresses are about half the usual values, amd the critical presmce on the roof depemis on the actual c o n t ~ area. Tests showed that to iml~ove roof stability the level of h~rizental %0nails stresses on ~he s~face of ~he ~ of t h e worki~s must be reduced. To achieve this, t h e diatribution of nominal b e a r i ~ capacity must be modified, ezd a ~stantlal Inarease in p r - l ~ - ~ s ~ bearlx~ capacity relative %0 wcad~.~ eapaclty i s Decessary. The co~Li~ions could be s~isfied if shield ~ype s u l ~ s were used.Auth.
626 KO~OPA,W S~e~@~h and beariDg capacity of an iDilvidual h~ullc prop under static loading assessed from c a l c u l a t i o n s a ~ s t u d i e s on a t o s t r i g . In P o l i s h . A d e s c r i p t i o n i s g i v e n o f a method o f c a l c u l a t i o r ~ t h e