- Email: [email protected]
Annual report 1979–1980
82A
815012 ON THE O ~ DESIGN OF ROCK MECHANICS PARAMETRIC STUDIES WITH ~/MERICAL MODELS Klasi, M L Proc 21st US Symposium on Rock Mechanics, Rolla, Missouri, 28-30 May 1980, P566-56 9 A specific technique from the statistical theory of design of experiments is applied to a ~xmerical parametric study in rock mechanics. The parametric study involves excavation of an uniergrouni cavern with s e v e n parameters. Each perameter is assumed to take on two values: a mean value and an extreme value. The method u s e d g i v e s experimen~cal d e s i g n s c a l l e d n ~ l t i factorial designs. The minimum design for this example called fcr eight numerical e x p e r i m e n t s . The elgh% e×periments give sufficient information to compute the effects of each parameter on the experimental outcome. The outcome of each m m ~ i c a l experiment is a factor of safety computed from a pressure sensitive failure criterion. Two cases were considered: intact rock and Jointed rock. Far intact rock cchesion was the most critical parameter while for Jointed rock the most critical parameter was Joint a ~ e . Auth.
ie, indepe~ient of the assumed functional form of the statistical distribution of trace lengths, and no knowledge of the actual lengths of the observed traces is required. Under the very general assumption that trace midpoints are raniomly and homogeneously distributed, all that needs to be known about each trace observed is whether it is censored at one or both ends. The method is restricted to a set of parallel traces of arbitrary direction. 815017 ESTIMATION OF DISCONTINUITY SPACING AND TRACE LENGTH USING SCANLINE SURVEYS Priest, S D; Hudson, J A Int J Rock Mech Min Sci, V18, N3, Jure 1981, P138-197 An expression is Presented which gives the degree of confidence that can be assigz~i to the measured mean d~ scontinuity spacing. A reduced form of this e~pression is obtained fc~ cases where the discontinuity spacings follow the negative exponential distribution. The Precision of discontinuity frequency ar~ RQD estimates is also explained. The distribution of trace lemgths ~oducei by the intersection of planar discontinuities with a planar rock face is used to determine the distribution of trace lengths, the distribution of semi-trace lengths and the distribution of censored semi-trace lemgths intersected by a raniomly located scanllne. Comperison of the actual and sampled distributions demonstrates the bias introduced by scanline sampling of trace lengths. Relations between the distributions can be used to Produce ~ l y t i c a l or graphical methods of estimating mean trace length from censored measurements at exposures of 1~m~ted extent.
8z~oz3 ACOUSTIC
~41SSION AS APPLIED TO ROCK AND SOIL, ITS HISTORY, BASIC THEORY AND SEVERAL CASE STUDIES Leaird, J D Proc 21st US Symposium on Rock M~_hanics, Rolls, Missouri, 28-30 May 1980, P616-621
Case studies describe (i) slope stability monltori~ with acoustic emission (2) development of a aim@le channel acoustic s y s t e m u s e d for roc~burst warning ard (3) techniques to determine the so1~ce location of saoustlc emission activity.
815o18
81~01~ GROUP APPROACH TO ROCK MECHANICS RESEARCH Isaac, A K; em~rt, B G D Proc 21st US Symposit~ on Rock Mechanics, Rolls, Missot~i, 28-30 May 1980, P710-719
A model has been developed that predicts the hydrostatic amd o~--dimenalomal strain, stressvolume relationship for Ix~rous rocks with various fluid contents. The model uses J~--ical ani penny-shaped pares aml Imclndes diatributlons in both size amd separations of these pares. Same of the pores are i::tercomnecte~ to allow the Passage of fluid as the porosity changes. The model is calibrated to the dry hydrostatic pressure-volmne relationship ani is then used to Predict the stress-volmne relationships for saturated or partially saturated r o c k s ~ The model Predictions are compared to the experimental results for Mr. Helen tuff. Auth.
Presents the research techniques and aims of the Strata Mechanics Research Grou~, Cardiff, in gateroed stud coal face investigations. 81~015 ANNUAL REPORT 1979-80 CSIRO Institute of Earth Resources, 1980, 74F Ccm~rlses reports from the 9 Divisions ami 2 units c c m ~ I s i ~ the Institute of Earth Resources (ImcltKLingthe Divisions of Applied Oeomech~nics, Mineral E ~ d m e e r i ~ ami Soils), organised u~ler the followi~ subject headlmgs: land, water, minerals, energy, and atmos~ere.
815o19 Avail: The Institute, PO Bc~ 225, Dickson, ACT 2602, Australia
Properties of Rocks and Soils 815016 ESTIMATING THE MEAN L~2~TH OF DISCONTINUITY TRACES Pah.l, P J Int J Rock Mech Min Scl, VI8, N3, June 1961, P221-228 A technique i s proposed for estimating the mean trace length of discontinuities observed in mine drive walls. The method is distribution-free,
COMPL'I~R MCDEL FOR STRESS-VQLt~4E RELATIONSHIPS OF POROUS ROCKS WITH VARIOUS SATURATIONS Abey, A E Rock Mech, V13, N~, March 1981, P235-2~
ANISOTROFZ OF DILATANCY OF SLATES (IN FRENCH) Lerau, J; Salnt-Leu, C; Sirieys, P Rock Mech, VI3, N3, Feb 1981, P185-196 Triaxiai com~ession tests were performed on cyli~rical samples of Lacaune slate (Tam) with c o n f i n i n g l ~ e s s u r e up t o 0 . 8 Kb. ~ 1 1 straAns indicate an initial elastic crthotro~y of revolution. Increase of confining pressure reduces the anlsotropy of the material. As the strain increases, as for pseudo-isotropic rocks, dilatancy occurs b u t only for orientations of the ma~or principal compression located inside a cone of revolution, the come of dilatamcy. T h i s d i l a t a ~ c y , d u e t o m i c r o c r a c k i n g , is a function o f a r i e n t a t i o n a ~ . c o n f i n i n g p r e s s ~ = e . Outside the cone of dilatancy the inelastic strain is deviatoric. The intensity of the
815012 ON THE O ~ DESIGN OF ROCK MECHANICS PARAMETRIC STUDIES WITH ~/MERICAL MODELS Klasi, M L Proc 21st US Symposium on Rock Mechanics, Rolla, Missouri, 28-30 May 1980, P566-56 9 A specific technique from the statistical theory of design of experiments is applied to a ~xmerical parametric study in rock mechanics. The parametric study involves excavation of an uniergrouni cavern with s e v e n parameters. Each perameter is assumed to take on two values: a mean value and an extreme value. The method u s e d g i v e s experimen~cal d e s i g n s c a l l e d n ~ l t i factorial designs. The minimum design for this example called fcr eight numerical e x p e r i m e n t s . The elgh% e×periments give sufficient information to compute the effects of each parameter on the experimental outcome. The outcome of each m m ~ i c a l experiment is a factor of safety computed from a pressure sensitive failure criterion. Two cases were considered: intact rock and Jointed rock. Far intact rock cchesion was the most critical parameter while for Jointed rock the most critical parameter was Joint a ~ e . Auth.
ie, indepe~ient of the assumed functional form of the statistical distribution of trace lengths, and no knowledge of the actual lengths of the observed traces is required. Under the very general assumption that trace midpoints are raniomly and homogeneously distributed, all that needs to be known about each trace observed is whether it is censored at one or both ends. The method is restricted to a set of parallel traces of arbitrary direction. 815017 ESTIMATION OF DISCONTINUITY SPACING AND TRACE LENGTH USING SCANLINE SURVEYS Priest, S D; Hudson, J A Int J Rock Mech Min Sci, V18, N3, Jure 1981, P138-197 An expression is Presented which gives the degree of confidence that can be assigz~i to the measured mean d~ scontinuity spacing. A reduced form of this e~pression is obtained fc~ cases where the discontinuity spacings follow the negative exponential distribution. The Precision of discontinuity frequency ar~ RQD estimates is also explained. The distribution of trace lemgths ~oducei by the intersection of planar discontinuities with a planar rock face is used to determine the distribution of trace lengths, the distribution of semi-trace lengths and the distribution of censored semi-trace lemgths intersected by a raniomly located scanllne. Comperison of the actual and sampled distributions demonstrates the bias introduced by scanline sampling of trace lengths. Relations between the distributions can be used to Produce ~ l y t i c a l or graphical methods of estimating mean trace length from censored measurements at exposures of 1~m~ted extent.
8z~oz3 ACOUSTIC
~41SSION AS APPLIED TO ROCK AND SOIL, ITS HISTORY, BASIC THEORY AND SEVERAL CASE STUDIES Leaird, J D Proc 21st US Symposium on Rock M~_hanics, Rolls, Missouri, 28-30 May 1980, P616-621
Case studies describe (i) slope stability monltori~ with acoustic emission (2) development of a aim@le channel acoustic s y s t e m u s e d for roc~burst warning ard (3) techniques to determine the so1~ce location of saoustlc emission activity.
815o18
81~01~ GROUP APPROACH TO ROCK MECHANICS RESEARCH Isaac, A K; em~rt, B G D Proc 21st US Symposit~ on Rock Mechanics, Rolls, Missot~i, 28-30 May 1980, P710-719
A model has been developed that predicts the hydrostatic amd o~--dimenalomal strain, stressvolume relationship for Ix~rous rocks with various fluid contents. The model uses J~--ical ani penny-shaped pares aml Imclndes diatributlons in both size amd separations of these pares. Same of the pores are i::tercomnecte~ to allow the Passage of fluid as the porosity changes. The model is calibrated to the dry hydrostatic pressure-volmne relationship ani is then used to Predict the stress-volmne relationships for saturated or partially saturated r o c k s ~ The model Predictions are compared to the experimental results for Mr. Helen tuff. Auth.
Presents the research techniques and aims of the Strata Mechanics Research Grou~, Cardiff, in gateroed stud coal face investigations. 81~015 ANNUAL REPORT 1979-80 CSIRO Institute of Earth Resources, 1980, 74F Ccm~rlses reports from the 9 Divisions ami 2 units c c m ~ I s i ~ the Institute of Earth Resources (ImcltKLingthe Divisions of Applied Oeomech~nics, Mineral E ~ d m e e r i ~ ami Soils), organised u~ler the followi~ subject headlmgs: land, water, minerals, energy, and atmos~ere.
815o19 Avail: The Institute, PO Bc~ 225, Dickson, ACT 2602, Australia
Properties of Rocks and Soils 815016 ESTIMATING THE MEAN L~2~TH OF DISCONTINUITY TRACES Pah.l, P J Int J Rock Mech Min Scl, VI8, N3, June 1961, P221-228 A technique i s proposed for estimating the mean trace length of discontinuities observed in mine drive walls. The method is distribution-free,
COMPL'I~R MCDEL FOR STRESS-VQLt~4E RELATIONSHIPS OF POROUS ROCKS WITH VARIOUS SATURATIONS Abey, A E Rock Mech, V13, N~, March 1981, P235-2~
ANISOTROFZ OF DILATANCY OF SLATES (IN FRENCH) Lerau, J; Salnt-Leu, C; Sirieys, P Rock Mech, VI3, N3, Feb 1981, P185-196 Triaxiai com~ession tests were performed on cyli~rical samples of Lacaune slate (Tam) with c o n f i n i n g l ~ e s s u r e up t o 0 . 8 Kb. ~ 1 1 straAns indicate an initial elastic crthotro~y of revolution. Increase of confining pressure reduces the anlsotropy of the material. As the strain increases, as for pseudo-isotropic rocks, dilatancy occurs b u t only for orientations of the ma~or principal compression located inside a cone of revolution, the come of dilatamcy. T h i s d i l a t a ~ c y , d u e t o m i c r o c r a c k i n g , is a function o f a r i e n t a t i o n a ~ . c o n f i n i n g p r e s s ~ = e . Outside the cone of dilatancy the inelastic strain is deviatoric. The intensity of the