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Rock mechanics in productivity and protection. Proceedings of the 25th symposium on rock mechanics, Evanston, Illinois, 25–27 June 1984
197A
856241 Effect of mining-related seismicity on excavations at East Rand Proprietary Mines, Limited Van Antwerpen, H E F: Spengler, M G Proc 1st International Congress on Rockbursts and Seismicity in Mines, Johannesburg, Sept 1982 P235-243. Publ Johannesburg. S A I M M , 1984 Rock burst frequency at East Rand Proprietary Mines, South Africa, has increased with the depth and extent of mining. Rock bursts are often associated with faults and dykes which are stronger than surrounding rock. The preventative and protective methods of reducing damage are described. Longwall mining with systematic stabilising pillars, planning and control of stoping geometry and face shape, and the use of active support systems have reduced problems caused by rock burst. 856242
Development of a wireline hydrofracturing technique and its use at a site of induced seismicity Haimson, B C; Lee, M Y In: Rock Mechanics in Productivity and Protection (paper to the 25th Symposium on Rock Mechanics, Evanston, Illinois,
25-27 June 1984) P194-203. Publ New York: AIME, 1984 A wireline hydrofracturing technique for in situ stress measurement has been developed, which eliminates the need for drill rig and drill rod and is fast and cheap to use. It was used at a site near the Monticello reservoir, South Carolina, USA, and was able to identify stress conditions which may explain impoundment related earthquakes. Results were in good agreement with previous tests in the same hole.
856243 Rock Mechanics in Productivity and Protection. Proceedings of the 25th Symposium on Rock Mechanics, Evanston, Illinois, 25-27 June 1984 Dowding, C H (editor): Singh, M M (editor) New York. AIME. 1984, 1222P Sections include: fracture mechanics (theory and experimental); fracture modelling and field verification for gas extraction; in situ stress; analytical techniques: behaviour under special conditions: characterisation studies: characterisation studies - in situ; properties and characteristics of porous media; mining ground control; ground control in coal mining: longwall mining ground control; induced mining subsidence: machine-rock interaction; protective structure design: tunnel support requirements; foundations and slopes: blast fragmentation: blasting case histories; wave propagation: nuclear waste isolation. 856244
Numerical and physical studies of fluid-driven fracture propagatiaon in jointed rock Shaffer, R J: Thorpe, R K: ingraffea, A R; Heuze, F E In: Rock Mechanics in Productivity and Protection (paper to the 25th Symposium on Rock Mechanics, Evanston, Illinois, 25-27 June 1984) P117-126. Pub/New York: AIME. 1984 Hydraulic fracturing of rock masses is a complex process, coupling fracture propagation in discontinuous media and fluid flow in discrete channels. The current status of the F E F F L A P code (finite element fracture and flow analysis program), a numerical model of these processes, is described. Laboratory experiments on hydrostatic fracturing across slanted interfaces between dissimilar materials, in blocks loaded in biaxial compression are described.
Planning, g e o t e c h n i c a l and structural m a p p i n g 856245
Prediction and performance Cocks, G C Proc 4th Australia-New Zealand Conference on Geomechanics, Perth, Western Australia, 14-18 May 1984 V1, P291-293. Publ Barton: Inst ofEngineers. 1984 Review of the eleven papers included in this session which relate to settlement. The manner in which geotechnical predictive methods have been developed, and their limitations, are briefly examined. 856246
Geotechnical aspects of the Bell Bay anchored retaining wall Chandler, B C; Cannon, J G Proc 4th Australia-New Zealand Conference on Geomechanics, Perth, Western Australia, 14-18 May 1984 V1, P294-299. Publ Barton. Inst ~f Engineers, 1984 Geotechnical aspects of the design and construction of an 8m high, 350m long sheet pile retaining wall. supported by 340 permanent soil anchors, are reviewed. Apart from designing the wall to resist at rest soil conditions in its completed state, it was necessary to take into account the staged method of construction and the influence of groundwater. Anchors used both bar and strand tendons and each anchor was required to have a minimum ultimate capacity of 800kN. Construction monitoring was an essential part of the project. Load cells, inclinometers, measurement surveys and piezometers used to assess the performance of the wall are discussed.
856247 Laboratory hydraulic fracturing stress measurements in salt Boyce, G M : Doe, TW: Majer. E In: Rock Mechanics in Productivity and Protection (paper to the 25th Symposium on Rock Mechanics, Evanston, Illinois,
25-27 June 1984) P95-102. Publ New York: AIME, 1984 Laboratory tests on 15cm diameter salt samples, loaded under hydrostatic stress conditions, examined influence of time, confining pressure, flow rate, borehole diameter and packers on breakdown pressure for hydraulic fracturing. Tests in a polyaxial loading frame determined whether hydraulic fracturing could be used to measure non-hydrostatic stresses. The behaviour of salt (to 64 hours) was not time-dependent but elastic methods of fracture analysis could not explain low breakdown pressures for confining pressures over 7MPa or lack of dependence of breakdown pressure on horizontal stress ratio in non-hydrostatic tests. Hydraulic fracturing may not be an effective stress measurement technique for salt because of its insensitivity to non-hydrostatic stresses.
C o r e recovery, logging, probing, boring and s a m pling 856248
Use of settlement monitoring for roadworks construction control Robertsom N F Proc 4th Australia-New Zealand Conference on Geomechanics, Perth, Western Australia, 14-18 May 1984
VI, P321-328. Publ Barton: lnst ~?/"Engineers, 1984 A settlement management approach relying heavily on settlement monitoring and interpretation during construction is described. The determination before construction of expected settlement behaviour and desired behaviour criteria, measurement and rapid interpretation of behaviour as it is occurring, and implementation, if necessary, of action during construction to ensure that the criteria are satisfied are included. The
856241 Effect of mining-related seismicity on excavations at East Rand Proprietary Mines, Limited Van Antwerpen, H E F: Spengler, M G Proc 1st International Congress on Rockbursts and Seismicity in Mines, Johannesburg, Sept 1982 P235-243. Publ Johannesburg. S A I M M , 1984 Rock burst frequency at East Rand Proprietary Mines, South Africa, has increased with the depth and extent of mining. Rock bursts are often associated with faults and dykes which are stronger than surrounding rock. The preventative and protective methods of reducing damage are described. Longwall mining with systematic stabilising pillars, planning and control of stoping geometry and face shape, and the use of active support systems have reduced problems caused by rock burst. 856242
Development of a wireline hydrofracturing technique and its use at a site of induced seismicity Haimson, B C; Lee, M Y In: Rock Mechanics in Productivity and Protection (paper to the 25th Symposium on Rock Mechanics, Evanston, Illinois,
25-27 June 1984) P194-203. Publ New York: AIME, 1984 A wireline hydrofracturing technique for in situ stress measurement has been developed, which eliminates the need for drill rig and drill rod and is fast and cheap to use. It was used at a site near the Monticello reservoir, South Carolina, USA, and was able to identify stress conditions which may explain impoundment related earthquakes. Results were in good agreement with previous tests in the same hole.
856243 Rock Mechanics in Productivity and Protection. Proceedings of the 25th Symposium on Rock Mechanics, Evanston, Illinois, 25-27 June 1984 Dowding, C H (editor): Singh, M M (editor) New York. AIME. 1984, 1222P Sections include: fracture mechanics (theory and experimental); fracture modelling and field verification for gas extraction; in situ stress; analytical techniques: behaviour under special conditions: characterisation studies: characterisation studies - in situ; properties and characteristics of porous media; mining ground control; ground control in coal mining: longwall mining ground control; induced mining subsidence: machine-rock interaction; protective structure design: tunnel support requirements; foundations and slopes: blast fragmentation: blasting case histories; wave propagation: nuclear waste isolation. 856244
Numerical and physical studies of fluid-driven fracture propagatiaon in jointed rock Shaffer, R J: Thorpe, R K: ingraffea, A R; Heuze, F E In: Rock Mechanics in Productivity and Protection (paper to the 25th Symposium on Rock Mechanics, Evanston, Illinois, 25-27 June 1984) P117-126. Pub/New York: AIME. 1984 Hydraulic fracturing of rock masses is a complex process, coupling fracture propagation in discontinuous media and fluid flow in discrete channels. The current status of the F E F F L A P code (finite element fracture and flow analysis program), a numerical model of these processes, is described. Laboratory experiments on hydrostatic fracturing across slanted interfaces between dissimilar materials, in blocks loaded in biaxial compression are described.
Planning, g e o t e c h n i c a l and structural m a p p i n g 856245
Prediction and performance Cocks, G C Proc 4th Australia-New Zealand Conference on Geomechanics, Perth, Western Australia, 14-18 May 1984 V1, P291-293. Publ Barton: Inst ofEngineers. 1984 Review of the eleven papers included in this session which relate to settlement. The manner in which geotechnical predictive methods have been developed, and their limitations, are briefly examined. 856246
Geotechnical aspects of the Bell Bay anchored retaining wall Chandler, B C; Cannon, J G Proc 4th Australia-New Zealand Conference on Geomechanics, Perth, Western Australia, 14-18 May 1984 V1, P294-299. Publ Barton. Inst ~f Engineers, 1984 Geotechnical aspects of the design and construction of an 8m high, 350m long sheet pile retaining wall. supported by 340 permanent soil anchors, are reviewed. Apart from designing the wall to resist at rest soil conditions in its completed state, it was necessary to take into account the staged method of construction and the influence of groundwater. Anchors used both bar and strand tendons and each anchor was required to have a minimum ultimate capacity of 800kN. Construction monitoring was an essential part of the project. Load cells, inclinometers, measurement surveys and piezometers used to assess the performance of the wall are discussed.
856247 Laboratory hydraulic fracturing stress measurements in salt Boyce, G M : Doe, TW: Majer. E In: Rock Mechanics in Productivity and Protection (paper to the 25th Symposium on Rock Mechanics, Evanston, Illinois,
25-27 June 1984) P95-102. Publ New York: AIME, 1984 Laboratory tests on 15cm diameter salt samples, loaded under hydrostatic stress conditions, examined influence of time, confining pressure, flow rate, borehole diameter and packers on breakdown pressure for hydraulic fracturing. Tests in a polyaxial loading frame determined whether hydraulic fracturing could be used to measure non-hydrostatic stresses. The behaviour of salt (to 64 hours) was not time-dependent but elastic methods of fracture analysis could not explain low breakdown pressures for confining pressures over 7MPa or lack of dependence of breakdown pressure on horizontal stress ratio in non-hydrostatic tests. Hydraulic fracturing may not be an effective stress measurement technique for salt because of its insensitivity to non-hydrostatic stresses.
C o r e recovery, logging, probing, boring and s a m pling 856248
Use of settlement monitoring for roadworks construction control Robertsom N F Proc 4th Australia-New Zealand Conference on Geomechanics, Perth, Western Australia, 14-18 May 1984
VI, P321-328. Publ Barton: lnst ~?/"Engineers, 1984 A settlement management approach relying heavily on settlement monitoring and interpretation during construction is described. The determination before construction of expected settlement behaviour and desired behaviour criteria, measurement and rapid interpretation of behaviour as it is occurring, and implementation, if necessary, of action during construction to ensure that the criteria are satisfied are included. The