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Cross-borehole fracture mapping using electromagnetic geotomography
responsibilities, opportunities and ch~lenges for those with geophysic~l expertise are defined. These include: replacing the squiggly line format, developing verification site~ for method e~-~lustions, applying knowledge engineering and assUming responsibility for crucial national uroblems involving rock mechanics expertise. Auth. 833294 CROSS-BOREHOLE FRACTURE ~tqFFING USING ELECTROMAGN'E~IC GEOT~.!OGP~I=~Y Ramirez, A L; Deadrlck, F J; Lytle, R ,! Proc 23rd Fymposlum on Rock Mechanics, Berkeley, 25-27 August ]9@2, P57-64. Pub.]. New York: ='.~ ~ , 1982 Describes the e ~ l ~ m t i o n of a new geophysical technique used to m p f r a c t u r e s between boreholes: electromagnetic geotomogra!d~v used in conJunction wlth salt water tracers. An experiment has been performed in a granitic rock mass. Geotomographlc images have been generated and compared with bore_hole geophysical data: neutron logs, acoustic velocity logs, caliper logs and acoustic televiewer records. C~nparisons between the images and the geophysical logs indicate that clusters of fractures were detected but single fractures were not. Auth. 833295 FIREFLOOD ~C[CROSEIS~IC MONITORING: ROCK MECHANICS IM~LICAT!ON~ Dusseault, M B; Nyland, E Proc 23rd symposium on Rock Mechanics, Berkeley, 25-27 August 1982, P1065-1076. Publ New York: A~, 1982
Investigates the d::ta prOcessing and intervret~tion techriques required to determine the in sltu properties of fr~ctured rocks from recorded wsveforms produced by ~ bor~ho!e ~ coustic logging device. 833298 RFJECTION CRITERION FOR D~!~CT!0N 0F C L U . : ~ : If~ 0R!ENTATI0.~ DATA Hahtab, !' Yegulall, T " Proc 23rd ~ymposlt~n on Rock Mech~rlcs, Berkeley, 25-27 August 1982, P!i6-123. Publ N ~ York: AD~,
1982
Presents an approach for clustering fr:~cture orientation data. D~ta are projected on the surface of the unit upper hemisphere <:nd the clustering approach is applied in 3 steps: (1) the randomness test and the identification of dense clusters, (2) the definition of dense cluster statistics using Bingham's distribution, and (3) the rejection of e~xtre~J£ data based on Chauvenet's criterion. The criterion is applied to data from ~an M~nuel mine, ~rizona, U ~ and Stripe mine, ~eden.
Subjects Peripheral to Geomechanics Concrete technology See: 833230
Seismic signals generated in a pilot flrefloed in a high permeability sand reservoir were monitored by a system of surface selamometers and borehole hydrophones. Spectral frequency analysis and knowledge of the material properties indicate that the events are shears of a stickslip nature, associated with straln-weakenlng behaviour of the over-compacted reservoir sands. It is concluded that the recorded events are associated with the fire front and may be used to map its presence and velocity.
Presentation and interpretation of data 833296 CCN~JTHR GENERATION OF INCLINED H~4!SPHERE FROJECTIONS. TECHNIC:~L NOTE Priest, 2 D Int J Rock Vech Min ~ci, V20, N!, Feb 1983, Fh3-47 Explains how a conventional lower hemisl~here projection, used for the determination of kinematic feasibility, slide direction and vol~ne of polyhedral rock blocks, can be generated numerically. The input for plotting an inclined hemispherical projection is achieved by rotstlon of vectors. Examples of both lower and inclined hemispherical projections produced on a microcomputer driving a dot matrix Irinter nre given. 833297 ACOUSTIC MODEs OF PROPAGATION IN THE BOREHOLE AND THEIR REL&TIONSHIP TO ROCK PROPERTIES Paillet, F L; ~Jhite, J E Geophysics, V~7, NS, At%Z ]982, P1215-1228
Snow and ice mechanics 833299 FRAC~T~RE ~.~CHANICfJ. }40DELS OF DRY SLAB AVf~LANCHE RELEASE McClung, D M J Geophys Res, V86, NBII, I0 Nov 1981, P10783-
1o79o Experimental evidence shows that snow is a pressure sensitive, dilatant, straln-softendng materlal in slow, constant rate, shear deformation. When strain softening initiates in a weak layer underneath a snow slab, avalanche release is hypothesized to be possible with or without addltlo~l loading. Specifically, two cases are discussed: (I) a shear-crack-llke disturbance can initiate after formation of a sllp surface in the weak layer and traverse the layer by ~ self-propagJting ~rogresslve failure with or even without loading, and (2) a selfPrOpagating she~r instability can develop when a region of the weak layer is driven past peak shesr strength by loading. For these cases the implied fracture sequence, fracture geometry, time scale of release, and temperature effects are discussed nnd shown to be consistent with the known facts of dry slab nv~lanche release. Auth.
Investigates the d::ta prOcessing and intervret~tion techriques required to determine the in sltu properties of fr~ctured rocks from recorded wsveforms produced by ~ bor~ho!e ~ coustic logging device. 833298 RFJECTION CRITERION FOR D~!~CT!0N 0F C L U . : ~ : If~ 0R!ENTATI0.~ DATA Hahtab, !' Yegulall, T " Proc 23rd ~ymposlt~n on Rock Mech~rlcs, Berkeley, 25-27 August 1982, P!i6-123. Publ N ~ York: AD~,
1982
Presents an approach for clustering fr:~cture orientation data. D~ta are projected on the surface of the unit upper hemisphere <:nd the clustering approach is applied in 3 steps: (1) the randomness test and the identification of dense clusters, (2) the definition of dense cluster statistics using Bingham's distribution, and (3) the rejection of e~xtre~J£ data based on Chauvenet's criterion. The criterion is applied to data from ~an M~nuel mine, ~rizona, U ~ and Stripe mine, ~eden.
Subjects Peripheral to Geomechanics Concrete technology See: 833230
Seismic signals generated in a pilot flrefloed in a high permeability sand reservoir were monitored by a system of surface selamometers and borehole hydrophones. Spectral frequency analysis and knowledge of the material properties indicate that the events are shears of a stickslip nature, associated with straln-weakenlng behaviour of the over-compacted reservoir sands. It is concluded that the recorded events are associated with the fire front and may be used to map its presence and velocity.
Presentation and interpretation of data 833296 CCN~JTHR GENERATION OF INCLINED H~4!SPHERE FROJECTIONS. TECHNIC:~L NOTE Priest, 2 D Int J Rock Vech Min ~ci, V20, N!, Feb 1983, Fh3-47 Explains how a conventional lower hemisl~here projection, used for the determination of kinematic feasibility, slide direction and vol~ne of polyhedral rock blocks, can be generated numerically. The input for plotting an inclined hemispherical projection is achieved by rotstlon of vectors. Examples of both lower and inclined hemispherical projections produced on a microcomputer driving a dot matrix Irinter nre given. 833297 ACOUSTIC MODEs OF PROPAGATION IN THE BOREHOLE AND THEIR REL&TIONSHIP TO ROCK PROPERTIES Paillet, F L; ~Jhite, J E Geophysics, V~7, NS, At%Z ]982, P1215-1228
Snow and ice mechanics 833299 FRAC~T~RE ~.~CHANICfJ. }40DELS OF DRY SLAB AVf~LANCHE RELEASE McClung, D M J Geophys Res, V86, NBII, I0 Nov 1981, P10783-
1o79o Experimental evidence shows that snow is a pressure sensitive, dilatant, straln-softendng materlal in slow, constant rate, shear deformation. When strain softening initiates in a weak layer underneath a snow slab, avalanche release is hypothesized to be possible with or without addltlo~l loading. Specifically, two cases are discussed: (I) a shear-crack-llke disturbance can initiate after formation of a sllp surface in the weak layer and traverse the layer by ~ self-propagJting ~rogresslve failure with or even without loading, and (2) a selfPrOpagating she~r instability can develop when a region of the weak layer is driven past peak shesr strength by loading. For these cases the implied fracture sequence, fracture geometry, time scale of release, and temperature effects are discussed nnd shown to be consistent with the known facts of dry slab nv~lanche release. Auth.