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Rockburst and discontinuity analysis
189A vertical principal stresses. Problems m underground rock engineering caused by the existence of in situ stress, and ways of using the favourable aspects and -~oiding unfavourable aspects are examined.
In Situ Stress Causes and nature of in situ stress 875132 Thrust faults in southern Illinois basin - result of contemporary stress? Nelson, W J: Bauer. R A Bull Geol Soc Am I'98..V3. March 1987, P302-307
Many north facing thrust faults are observed in mines in southern Illinois and adjacent Kentucky, with displacements up to 10m. No known ancient tectonic stress field or nontectonie process can account for their appearance. A contemporary E-W to E-NE-W-SW stress field is indicated by local mechanisms of earthquakes, hydrofracturing, borehole breakouts and overcoring, with sufficient magnitude to cause brittle fracture of coal and shale in situ. It is concluded that the north-trending thrust faults are in response to this contemporary stress field.
875 ! 36 Preliminary study of in-situ stress field in the Three-Gorge dam area Chen Yangsheng: Liu Yunfang: Zhang Min: Chen Renxian
Proc International Symposium on Engineering in Complex Rock Formations, Beijing, 3-7 .Vorember, 1986 P149-154. P,;bl Beijing: Science Press. I9,~6 A mathematical model using background ana',',sis is first presented to describe the area of the Huangling anticline. It includes analysis of topograph.,,, geology, and the effects of tectonic, depositional, or denudation actions for each stratum. Results agree well with in situ stress measurements made over a period of .','ears using a variety of techniques, and suggest that structural movements are not expected.
875133 Hydraulic fracturing stress measurements and in-situ stress field in the Kanto-Tokai area. Japan Tsukahara, H; lkeda, R
Tectonophysics V135. N4, April 1987. P329-345 About 90 sets of in situ stresses have been obtained from boreholes 100-800m deep in the Kanto-Tokai area since 1978. The data are interesting from earthquake prediction and tectonic aspects. Maximum and minimum horizontal stresses increase linearly with depth for each borehole, as do the differences betx~een maximum and minimum principal stresses. Results are discussed in terms of local seismicity and the tectonic structure of the surrounding area.
875134 ln-situ stress measurements at some different geological formations in Korea Han-Uk Lim: Chung-ln Lee Proc International Symposium on Engineering in Complex
Rock Formations, Beijing, 3-7 November, 1986 P121-127. Publ Beijing: Science Press. 1986 In situ stresses were measured at four sites in Korea at depths of 105-802m, using the triaxial borehole deformation gauge method of strain relief. The major principal stress in most cases was parallel to the predominant orientation of local fractures. There ',,,'as a significant horizontal compressive stress throughout the area examined. Magnitude and direction of the major principal stresses were affected by such factors as topography', structural features and erosional processes.
875135 In situ stress measurements, tectonic stress field and engineering Li Fangquan
Proc Internath~nal Symposium on Engineering in Complex Rock Formations. Beijing, 3-7 November, 1986 P128-134. Publ Beijing Science Press. 1986 The essential characteristics of the in situ stress fields in China are discussed, including variations with depth, variations in direction, and variations in the ratio between horizontal and
Measurement of in situ stress See also: 875016
875137 Hydraulic fracturing experiment at the University of Regina Campus McLennan, J D: Hasegawa. H S; Roegiers. J C; Jessop. A M Can Geotech J V23, N4, .Voc 1986, P54S-555
Hydraulic fracturing experiments ha',e been carried out at depths between 2062 and 2t 15m in a well intended for use in a geothermal energy project in Saskatchev,an. Canada. In situ stresses have been calculated from the hydrofracturing data. Geophysical and seismotectonic implications concerning expected faulting mechanisms in the formations are considered.
875138 Rockburst and discontinuity analysis Acevedo, P; Arjona, R; Medrano, S
Proc International Symposium on Large Rock Carerns, Helsinki, 25-28 August 1986 I"l, P645-652. Publ O.~Jbrd. Pergamon Press, 1986 An empirical method of assessing in situ stress and rock burst potential has been developed, based on acoustic emission experiments. A characteristic curve, a plot of acoustic behaviour during Brazilian tests versus % of failure load. was plotted and seen to be of the same shape for andesite, diorite and dacite rocks. Comparison of acoustic emission from rock faces, where the stress regime is similar to the Brazilian test,allows in sitt, stress and rock burst potential to be assessed.
~. 1987 Pergamon Journals Ltd. Reproduction not permitted
In Situ Stress Causes and nature of in situ stress 875132 Thrust faults in southern Illinois basin - result of contemporary stress? Nelson, W J: Bauer. R A Bull Geol Soc Am I'98..V3. March 1987, P302-307
Many north facing thrust faults are observed in mines in southern Illinois and adjacent Kentucky, with displacements up to 10m. No known ancient tectonic stress field or nontectonie process can account for their appearance. A contemporary E-W to E-NE-W-SW stress field is indicated by local mechanisms of earthquakes, hydrofracturing, borehole breakouts and overcoring, with sufficient magnitude to cause brittle fracture of coal and shale in situ. It is concluded that the north-trending thrust faults are in response to this contemporary stress field.
875 ! 36 Preliminary study of in-situ stress field in the Three-Gorge dam area Chen Yangsheng: Liu Yunfang: Zhang Min: Chen Renxian
Proc International Symposium on Engineering in Complex Rock Formations, Beijing, 3-7 .Vorember, 1986 P149-154. P,;bl Beijing: Science Press. I9,~6 A mathematical model using background ana',',sis is first presented to describe the area of the Huangling anticline. It includes analysis of topograph.,,, geology, and the effects of tectonic, depositional, or denudation actions for each stratum. Results agree well with in situ stress measurements made over a period of .','ears using a variety of techniques, and suggest that structural movements are not expected.
875133 Hydraulic fracturing stress measurements and in-situ stress field in the Kanto-Tokai area. Japan Tsukahara, H; lkeda, R
Tectonophysics V135. N4, April 1987. P329-345 About 90 sets of in situ stresses have been obtained from boreholes 100-800m deep in the Kanto-Tokai area since 1978. The data are interesting from earthquake prediction and tectonic aspects. Maximum and minimum horizontal stresses increase linearly with depth for each borehole, as do the differences betx~een maximum and minimum principal stresses. Results are discussed in terms of local seismicity and the tectonic structure of the surrounding area.
875134 ln-situ stress measurements at some different geological formations in Korea Han-Uk Lim: Chung-ln Lee Proc International Symposium on Engineering in Complex
Rock Formations, Beijing, 3-7 November, 1986 P121-127. Publ Beijing: Science Press. 1986 In situ stresses were measured at four sites in Korea at depths of 105-802m, using the triaxial borehole deformation gauge method of strain relief. The major principal stress in most cases was parallel to the predominant orientation of local fractures. There ',,,'as a significant horizontal compressive stress throughout the area examined. Magnitude and direction of the major principal stresses were affected by such factors as topography', structural features and erosional processes.
875135 In situ stress measurements, tectonic stress field and engineering Li Fangquan
Proc Internath~nal Symposium on Engineering in Complex Rock Formations. Beijing, 3-7 November, 1986 P128-134. Publ Beijing Science Press. 1986 The essential characteristics of the in situ stress fields in China are discussed, including variations with depth, variations in direction, and variations in the ratio between horizontal and
Measurement of in situ stress See also: 875016
875137 Hydraulic fracturing experiment at the University of Regina Campus McLennan, J D: Hasegawa. H S; Roegiers. J C; Jessop. A M Can Geotech J V23, N4, .Voc 1986, P54S-555
Hydraulic fracturing experiments ha',e been carried out at depths between 2062 and 2t 15m in a well intended for use in a geothermal energy project in Saskatchev,an. Canada. In situ stresses have been calculated from the hydrofracturing data. Geophysical and seismotectonic implications concerning expected faulting mechanisms in the formations are considered.
875138 Rockburst and discontinuity analysis Acevedo, P; Arjona, R; Medrano, S
Proc International Symposium on Large Rock Carerns, Helsinki, 25-28 August 1986 I"l, P645-652. Publ O.~Jbrd. Pergamon Press, 1986 An empirical method of assessing in situ stress and rock burst potential has been developed, based on acoustic emission experiments. A characteristic curve, a plot of acoustic behaviour during Brazilian tests versus % of failure load. was plotted and seen to be of the same shape for andesite, diorite and dacite rocks. Comparison of acoustic emission from rock faces, where the stress regime is similar to the Brazilian test,allows in sitt, stress and rock burst potential to be assessed.
~. 1987 Pergamon Journals Ltd. Reproduction not permitted