Rok M Sregh derved ro Rok M Chrerzo Go, W H, SRK Coulg, Perh, Weer Aurl, Aurl Upded vero o he pper pulhed he Jourl o Aurl Geoeh Vol 4 o Mrh 2006 ABSTRACT: The ee o rok regh key elee or he ly o y rok exvo, oh ope p d udergroud. There hve ee ep o e h regh ug ule rok regh rero hvg pu derved ug Rok M Clo ye., The o well developed rero he Hoek-Brow Flure Crer ug he Geoehl Sregh Idex (Hoek, 2002 pu. Depe populry, he GSI h oe oee. Rok e wh derg rure requee d jo odo hve he e GSI vlue d hereore he e regh hrer would e ppled. To ddre h ue, h pper dere ehod o deere he pu o he rero o he o he jo odo d rurg o he rok. ITRODUCTIO The ee o rok regh key elee y rok exvo or oh, ope p d udergroud exvo. Whe uerl odel re ued ool o ly, h regh deed er o regh evelope. The evelope y e ler, lke Mohr Coulo or o ler lke h uggeed y Hoek [995]. There re eprl ehod h rele rok lo wh deg preer lke lope gle, ope-p d uppor, Bewk [989], Luher [990], Bro [974]. The lo ehod do o however drely provde he regh hrer.. The o-ler Hoek Brow rero rele he regh evelope o he rok lo hrough he GSI dex. Th ehod llow regh ee ed o ul d olleed o e, ly douy dey, douy odo, plu lorory oro lke uoed opreve regh. Oe drwk o h ehod h dere hrer o he rok, lke jo odo d douy dey, re oed gle uer, GSI, d h uer ued o e he rok regh. Two dere rok e hve he e GSI (Fgure u he jo odo d douy dey re dere, ulkely h oh rok e would hve he e regh. I he jo odo d douy dey re odered eprely pole o ee he rok regh or eh oe. 2 ROCK MASS STREGTH ASSESSMET BASED O ROCK MASS RATIG GSI The rok regh e evlued ug he Hoek Brow lure rer [Hoek, 995]. The regh evelope wre er o he prpl ree how Eq. (. Where he uoed opreve regh o he rok (UCS, d he preer, d re reled wh he rok rg hrough he GSI. Thee relohp re how Eq (2, ( d (4. (
Fgure : Correlo ewee GSI d rok propere d d preer deo. Roee [8] GSI 00 exp (2 28 4D GSI 00 exp ( 9 D GSI /5 ( e 20/ e 2 6 where erl o d D Dure For. A orrelo ewee he GSI dex d he rok quly e ee Fgure. (4 ROCK MASS STREGTH ASSESSMET BASED O JOIT SPACIG AD JOIT CODITIOS The GSI eve o hoe rok hrer h o luee rok regh. A ere o relohp re propoed h eek o prlly ddre h ue y dereg rok e hvg he e GSI. Thee relohp re uo o wo preer, d. uo o he hrer o he rurg d erlokg d uo o he jo odo. The vro o hee preer oepully how Fgure, For exple loky rok wh r jo ure odo gh hve GSI5, h e he loky odo hrerzed y he preer d he r ure odo y he preer,
The reoeded regh evelope Eq. (, ue he e preer urrely ued he Hoek Brow lure rero however propoed h, d re luled ug he ollowg relohp. x [ ( ( ( ( ] 2 x 2 (5 [ ( ( ( ( ] (6 4 x 4 x [ ( * 0.5 exp( 40 * 0.5 ] 0.6 0.4 exp (7 The uo ( d he preer x re uo o he Rok M Clo ye ued. The uo ( ued Eq. (5 d (6 e wre ug he geer or how Eq. (8 ( A ( B A exp( C( M exp( CM (8 [ ] The preer A, B, C d M ued o eh uo ( re how Tle. Tle : Preer A,B,C d M Fuo A B C M 0.4 0.69 0.25 40 2 0.04 0.60 0.25 40 4e- 0.25 0.6 40 4 0.0 4e-4 0.6 40 I reoeded h he drd rok lo ye re ued o evlue he preer d. I o hereore eery o o y ddol d o h urrely requred pu o hee ye. The rg or pg o doue d jo odo hould e ued o evlue he preer d. I por o oe h pper do o reoed o ue GSI drely o evlue he rok regh. I h pper, wo ye re reoeded o e ued wh he Eq. (5, (6 d (7, Bewk [989], d Luher [990].
Fgure 2: Eo o o / d The preer / d re reled o hge rure requey d jo odo. Hoek [995] preeed he dve vlue or hee preer how Fgure 2.The vlue o A, B d C Tle were ed o he vlue / how h gure Fuo dere he hge / wh hge he rure requey or VERY GOOD ure odo. The xu d u vlue or / re 0.60 d 0.7 how Fg. 2. Thee vlue were exrpoled o 0.69 d 0.4, oderg Fg h 6 degree o rurg d Fg. 2 how oly 4 Fuo 2 dere he hge / wh hge he rurg or VERY POOR ure odo. The xu d u vlue or / re 0.08 d 0.04. The vlue o 0.08 w reed o 0.60 eue he uer o jo ll he jo odo eoe le por eue here ew or o jo y gve lok o rok. For h reo he ro / u ree d eoe lghly lower h he ro / or ve rok wh ew jo wh good ure odo. The u vlue o 0.04 w kep he e. Fuo dere he hge h our o he vlue o wh hge he rure requey or VERY GOOD ure odo. The xu d u vlue or re 0.9 d 0.004 ded Fgure 2. The xu vlue w reed o 0.25 o oder hoe rok e hvg very ew jo how Fgure or ve rok d very good ure odo. The u vlue o 0.004 w kep he e. Fuo 4 dere he hge wh hge he rurg or VERY POOR ure odo. The xu d u vlue or re 0.0004 d 0.0 ded Fgure 2. Thee vlue where kep whou odo.
Preer. I he Hoek Brow lure rero he preer vre ewee 0.5 o 0.66 or rok o poor quly rok. I h pper propoed o ue Eq. (7 h llow he preer o vry ewee 0.6 o.0 wh hge. Thoe uer were ed o he o ler regh evelope o hghly rured rok lke rokll h h preer ewee 0.6 o 0.89 Idrr [99].. ROCK MASS STREGTH BASED O BIEIAWSKI S ROCK MASS RATIG SYSTEM RMR B The preer ued Bewk Rok M Rg (RMR B ye re: Sregh o I Rok Drll Core Quly RQD Spg o douy Codo o Doue (ed o douy legh, perure wdh, roughe, ll ype d hke o he weherg Groud Wer I RMR B ued Rok M Clo ye, he d preer u e luled ug Eq. (9 d (0 would e he rge o 0 o 40 po d he rge o 0 o 0. x 0 or Bewk ye. 40 ( RQDrg Spg 8 2 rg (9 Douy _ Codo rg (0.2 ROCK MASS STREGTH BASED O LAUBSCHER S ROCK MASS RATIG SYSTEM RMR L The preer ued Luher [990] Rok M Rg (RMR L ye re: Sregh o I Rok Drll Core Quly RQD Spe Douy Frure Frequey Codo o Douy (Jo Codo The ye provde wo wy o e he rurg. RQD d Spe Douy e ued ogeher or, ed Frure Frequey e ued. I oh e he rg vre ro 0 o 40. For jo odo he rg vre ro 0 o 40. The preer e luled ug Eq. ( or (2, he preer luled ug Eq. (. ould e he rge o 0 o 40 d ould e he rge o o 40 RQD Spg ( rg rg Frure _ Frequey rg (2 Douy _ Codo rg (
x 40 or Luher ye. 4 TESILE STREGTH AD EQUIVALET MOHR COULOMB STREGTH EVELOPE The ele regh or he rok e luled y eg Eq. ( d e luled ug Eq. (4. Th repree xl eo. For rle erl, he uxl ele regh equl o he xl ele regh (Hoek, 98. (4 I pole o lule equvle Mohr Coulo regh evelope or rge o oee deed y < < x (Hoek, 2002. The ollowg equo e ued o e he equvle ro φ d oheo. ( 6 (2 2( ( 6 φ (5 [ ] (2 (( ( (6 (2 ( ( ( 2 ( (6 Where x / A lerve ee or he ele regh e derved replg 0 d equo. Th gve u equo 7. (7 Equo 7 e olved ug erve ehod. I propoed o ue equo 8 wh rg vlue or gve y equo 9 where luled wh equo 4. I geerl h ehod produe ele regh lower h equo 4. (8 (9
5 EXAMPLES 5. STREGTH ASSESSMET BASED O BIEIAWSKI S ROCK MASS RATIG SYSTEM RMR B. A exple o he pplo o he propoed ye, wo rok e wh he e hrer exep jo odo d rurg re odered. The hge he rg uh h oh hve he lr RMR B 62 wh 00 MP d 2. Tle 2 how he rg or he dere rok hrer d he vlue d ued he regh lulo. Ilude he Hoek Brow regh preer d he equvle Mohr Coulo regh preer or x 2 MP. Tle 2: Sregh Preer Bed o Bewk rok rg ye. Preer Ce A Rg Ce B Rg UCS o rok 8 8 RQD 7 9 Spg 7 2 4 6 Jo Codo 5 5 26 26 Wer 5 5 RMR B 62 62.58.52.0e-.47e- 0.602 0.762 φ 47º 8º [MP] 0.55 0.6 Ce A rok wh le rure h rok B u wh o guge he jo. Ce B rok wh hgh level o rurg wh lghly rough ure d wehered ure. Beue he uer o rure le Ce B opred wh Ce A d he jo odo dere he regh luled dere depe hvg oh he e RMR. Fgure how he regh evelope or oh e.
Rok M Sregh ed o Bewk' Rok M Clo Sye 20.0 8.0 6.0 Prpl Sre [MP] 4.0 2.0 0.0 8.0 6.0 Ce A Ce B 4.0 2.0 0.0-0.5 0 0.5.5 2 Coee [MP] Fgure : Rok M Sregh Evelope Bed o Bewk Rok M Rg 5.2 STREGTH ASSESSMET BASED O LAUBSCHER S ROCK MASS RATIG SYSTEM RMR L. The ollowg exple ee he regh o hghly rured rok hvg le rough jo. The rg pplle o he dere hrer re how Tle. The preer re: 75 MP d 2. The rok lo ed o Luher [990] d Bewk [989] ye re RMR L 50 d RMR B 60 (GSI55. The preer led he le re hoe pplle o Bewk ye, Thee d were ued o deere he GSI. The regh o he rok w deered ug he Hoek Brow rero pplle o dured d udured rok. The equvle Mohr Coulo preer (.e, ro φ d oheo, luled or x 2 [MP] re luded he le ( x w hoe rrrly h exple or urher duo ee reeree [8]. Tle : Copro Sregh Ug Propoed Mehod d Hoek Brow Flure Crer Preer Luher RMR rg Bewk RMR rg UCS o rok 8 7 RQD (0% 0 Spg 2 2 5 0 Jo Codo 40 40 0 0 Wer 0 5 RMR B 50 60 (GSI55 Dure D0 D φ 4º 5º 8º [MP] 0.65.7 0.6
Tle how he ehod propoed o e he rok regh gve reole vlue o Mohr Coulo regh preer. Ug he GSI dex he regh o hghly rured le rok exreely hgh or oh, dured (D d udured rok (D0. A erl wh oheo he rge o 0.6 o.7 Mp d verl ewee 90 o 70 wh ou oderg he regh due o ro. I ulkely hghly rured rok u verl lope wh hee hegh. 6 COCLUSIO A ew pproh preeed o e he preer, d he Hoek Brow lure rero, The ehod ue he jo odo d rure requey v RQD d pg pu o he rero. Two Rok M Clo ye re odered,; Bewk d Luher. Ied o ug he overll Rok M Rg RMR derved ug oe o hee ye pu o he regh rero, wo ew preer ed o jo odo d rurg o he rok d re ued. Thee ew preer e evlued drely ro he RMR d o ew d requred. The proedure ddre deree jo odo d rurg h re o releed he rg ye. The propoed ehod deree ewee he regh o rok e wh hgh rurg d le rough jo d rok e wh low rurg d ooh jo wh gouge, eve hough hey gh hve he e rok rg. REFERECES [] Bro R, Le R, d Lude J (974 Egeerg lo o rok e or he deg o uel uppor, Rok Meh. 6(4, 89-29. [2] Bewk Z T (989 Egeerg rok lo, ew York, Wley [] Hoek E, (98 Sregh o joed rok e, 2 rd Rke Leure, Geoehque (, 87-22. [4] Hoek E, Crrz-Torre C, Corku B (2002 Hoek Brow lure rero 2002 Edo, Rol progr Roee. [5] Hoek E, Ker P K, Bwde W F (995 Suppor o Udergroud Exvo Hrd Rok. Blke [6] Idrr B, Wjewrde L S S, Blur A S, (99 Lrge le rxl eg o greywke rokll. Geoehque 4 (, 7 5. [7] Luher D H (990 A geoeh lo ye or he rg o rok e deg, J S Ar I M d Mel, Vol 90, o0, pp257,27 [8] Roee (2004, Rol progr.