- Email: [email protected]
The current situation of in-situ stress measurements in tunnelling
SITE INVESTIGATIONS:REMOTE SENSING fracturing field tests (two tests in overburden layers, the third one in a reservoir) are used to extract from the P,a and pf pressure values the maximum horizontal stress oH, the interpretation being based on linear fracture mechanics. (English summary)
966160 ISIS: an Instrument for measuring erosion Shear stress In Situ H. J. Williamson & M. C. Ockenden, Estuarine, Coastal & Shelf Science, 42(1), 1996, pp 1-18. An instrument for measuring shear stress for erosion in situ (ISIS) has been developed to measure the erosion shear stress of muddy sediments on intertidal mud fiats. Erosion shear stress is defined in this paper as the minimum applied bed shear stress required to initiate erosion and remove sediment from the bed surface. An applied shear stress is generated by the flow through and around a specially shaped bell head, which draws water radially across the bed into the centre of the bell head. The applied shear stress is a function of the distance from the bell head to the bed surface and the d~seharge through the system. The design of ISIS was assisted by the use of a computational numerical flow modelling package. (from Authors) 966161 Geotechnical investigations for a deep radioactive waste repository: in situ stress measurements R. Christiansson, J. A. Scarrow, A. P. Whittlestone & A. Wikman, in: Engineering geology o f waste disposal, ed S.P. Bentley, (Geological Society of London; Engineering Geology Special Publication, 11), 1996, pp 201-214. Comprehensive geotechnical investigations of potential repository sites for deep disposal of low- and intermediate-level solid radioactive wastes at Sellaficld, Cumbria and Dounreay, Caithness included drilling and testing cored boreholcs up to 2000 m deep. The investigation at Sellafield included the measurement of/n situ stresses using the overcoring technique at various depths in a 250 m deep, vertical borehole drilled from the surface. The equipment used to carry out these measurements was the Swedish Borre Probe. This project required/n situ stress measurements to be taken in a relatively large-diameter borehol¢, drilled in weak sedimentary rocks by wireline drilling techniques, and consequently, significant adaptations to the installation equipment. (from Authors) 966162 Prognostic estimation of the stress state of plagiogranites along the section of the Krivoi Rog ultradeep borehole (Ukraine) V. A. Korchin, T. S. Lebedev, P. A. Burtnyi & N. S. Kurlov, Geophysical Journal, 14(2), 1994, pp 223-244. In the course of drilling the ultradeep Krivoi Rog borehole it was established that some horizons, including those composed of plagiogranites, contained zones of borehole wall instability. Laboratory studies of their elastic anisotrnpy, showed that at certain depths the rocks were in a complex stress state. That state is a result of recent crustal movements, sufficient to cause fragmentation of the rock during decompression resulting from the drilling. (from Authors) 966163 Zum Stand der ln-situ Spannungsmessungen fur den Tunnelbau (The current situation of in-situ stress measurements in tunnelling) H. Bock & P. Hartkorn, Felsbau, 13(6), 1995, pp 363-366. With the increased acceptance of alternative non-overcoring stress measuring methods such as borehole slotting and hydraulic fracturing, the relevance of in situ stress measurements has increased in recent years. Examples of highdefinition borehole slotting tests are presented from various regions of Central Europe. (English summary)
261A
966164 Untersuchungen zu Gebirgsspannungen und -bewegungen in der Schwabischeu AIb (Investigations and considerations of the state of stress and ground movements) H. Hammer, S. Niedermeyer & T. Niedermeyer, Felsbau, 13(6), 1995, pp 367-373. During pre-feasibility studies for the projected railway line between Stuttgart and Augsburg a total of 20 boreholes were drilled and completed as either inclinometers or ground-water monitoring wells. Before completion, tests were carried out to determine hydraulic conductivities as well as hydro-frac measurements to establish the in situ primary stress strain relations. (English summary) 966165 Problemorientierte Auswertung geotechnischer Messungen (Advanced analysis of geotechnical displacement monitoring data new tools and examples of application) A. F. Steindorfer, W. Schubert & K. Rabensteiner, Felsbau, 13(6), 1995, pp 386-390. Geodetical displacement monitoring in tunnelling allows the determination of the displacement vector of each measured point in space. Data are plotted on time-displacement diagrams or as lines of influence for the single components of the displacement vector. Evaluation of monitoring data from several tunnels showed, that the orientation of the displacement vector can indicate primary stress directions and local stiffness variations in the rock mass. (English summary)
SITE INVESTIGATION AND FIELD OBSERVATION ~ General 966166 Surveying during a Siberian winter V. Obinyakov & A. Kopylov, Geomatics Info Magazine, 10(2), 1996, pp 24-25. Surveying under harsh Siberian conditions requires specific surveying instruments. For instance, ordinary opticalmechanical theodolites would not survive more than two winter seasons. Ordinary electronic total stations or GPS receivers will not operate normally due to extremely low temperatures near -40°C. There are occasions when surveyors have to heat instruments in fumes from burning wood in order to finish measurements. (Authors) 966167 An evaluation of environmental geology of Pingshan new city site in reservoir region of Xiangjiaba waterpower station (in Chinese) Hu Xiewen, Liu Hanchao, Chen Mingdong & Li Kewu, Journal - Chengdu Institute o f Technology, 22(2), 1995, pp 64-73. This paper investigates and analyses the engineering geological conditions of the new city site of Pingshan in the reservoir region of the Xiangjiaba waterpower station, Jinshajiang River. It also evaluates some environmental geological problems, for example, landslide and collapse, the stability of the foundation, the water source of water supply, etc. (English summary)
Remote sensing and photographic techniques 966168 Using satellite imagery, CAD, and GPS to develop an environmental and engineering baseline J. M. Ellis & P. B. Goodwin, Earth Observation Magazine, 4(10), 1995, pp 16-18.
966160 ISIS: an Instrument for measuring erosion Shear stress In Situ H. J. Williamson & M. C. Ockenden, Estuarine, Coastal & Shelf Science, 42(1), 1996, pp 1-18. An instrument for measuring shear stress for erosion in situ (ISIS) has been developed to measure the erosion shear stress of muddy sediments on intertidal mud fiats. Erosion shear stress is defined in this paper as the minimum applied bed shear stress required to initiate erosion and remove sediment from the bed surface. An applied shear stress is generated by the flow through and around a specially shaped bell head, which draws water radially across the bed into the centre of the bell head. The applied shear stress is a function of the distance from the bell head to the bed surface and the d~seharge through the system. The design of ISIS was assisted by the use of a computational numerical flow modelling package. (from Authors) 966161 Geotechnical investigations for a deep radioactive waste repository: in situ stress measurements R. Christiansson, J. A. Scarrow, A. P. Whittlestone & A. Wikman, in: Engineering geology o f waste disposal, ed S.P. Bentley, (Geological Society of London; Engineering Geology Special Publication, 11), 1996, pp 201-214. Comprehensive geotechnical investigations of potential repository sites for deep disposal of low- and intermediate-level solid radioactive wastes at Sellaficld, Cumbria and Dounreay, Caithness included drilling and testing cored boreholcs up to 2000 m deep. The investigation at Sellafield included the measurement of/n situ stresses using the overcoring technique at various depths in a 250 m deep, vertical borehole drilled from the surface. The equipment used to carry out these measurements was the Swedish Borre Probe. This project required/n situ stress measurements to be taken in a relatively large-diameter borehol¢, drilled in weak sedimentary rocks by wireline drilling techniques, and consequently, significant adaptations to the installation equipment. (from Authors) 966162 Prognostic estimation of the stress state of plagiogranites along the section of the Krivoi Rog ultradeep borehole (Ukraine) V. A. Korchin, T. S. Lebedev, P. A. Burtnyi & N. S. Kurlov, Geophysical Journal, 14(2), 1994, pp 223-244. In the course of drilling the ultradeep Krivoi Rog borehole it was established that some horizons, including those composed of plagiogranites, contained zones of borehole wall instability. Laboratory studies of their elastic anisotrnpy, showed that at certain depths the rocks were in a complex stress state. That state is a result of recent crustal movements, sufficient to cause fragmentation of the rock during decompression resulting from the drilling. (from Authors) 966163 Zum Stand der ln-situ Spannungsmessungen fur den Tunnelbau (The current situation of in-situ stress measurements in tunnelling) H. Bock & P. Hartkorn, Felsbau, 13(6), 1995, pp 363-366. With the increased acceptance of alternative non-overcoring stress measuring methods such as borehole slotting and hydraulic fracturing, the relevance of in situ stress measurements has increased in recent years. Examples of highdefinition borehole slotting tests are presented from various regions of Central Europe. (English summary)
261A
966164 Untersuchungen zu Gebirgsspannungen und -bewegungen in der Schwabischeu AIb (Investigations and considerations of the state of stress and ground movements) H. Hammer, S. Niedermeyer & T. Niedermeyer, Felsbau, 13(6), 1995, pp 367-373. During pre-feasibility studies for the projected railway line between Stuttgart and Augsburg a total of 20 boreholes were drilled and completed as either inclinometers or ground-water monitoring wells. Before completion, tests were carried out to determine hydraulic conductivities as well as hydro-frac measurements to establish the in situ primary stress strain relations. (English summary) 966165 Problemorientierte Auswertung geotechnischer Messungen (Advanced analysis of geotechnical displacement monitoring data new tools and examples of application) A. F. Steindorfer, W. Schubert & K. Rabensteiner, Felsbau, 13(6), 1995, pp 386-390. Geodetical displacement monitoring in tunnelling allows the determination of the displacement vector of each measured point in space. Data are plotted on time-displacement diagrams or as lines of influence for the single components of the displacement vector. Evaluation of monitoring data from several tunnels showed, that the orientation of the displacement vector can indicate primary stress directions and local stiffness variations in the rock mass. (English summary)
SITE INVESTIGATION AND FIELD OBSERVATION ~ General 966166 Surveying during a Siberian winter V. Obinyakov & A. Kopylov, Geomatics Info Magazine, 10(2), 1996, pp 24-25. Surveying under harsh Siberian conditions requires specific surveying instruments. For instance, ordinary opticalmechanical theodolites would not survive more than two winter seasons. Ordinary electronic total stations or GPS receivers will not operate normally due to extremely low temperatures near -40°C. There are occasions when surveyors have to heat instruments in fumes from burning wood in order to finish measurements. (Authors) 966167 An evaluation of environmental geology of Pingshan new city site in reservoir region of Xiangjiaba waterpower station (in Chinese) Hu Xiewen, Liu Hanchao, Chen Mingdong & Li Kewu, Journal - Chengdu Institute o f Technology, 22(2), 1995, pp 64-73. This paper investigates and analyses the engineering geological conditions of the new city site of Pingshan in the reservoir region of the Xiangjiaba waterpower station, Jinshajiang River. It also evaluates some environmental geological problems, for example, landslide and collapse, the stability of the foundation, the water source of water supply, etc. (English summary)
Remote sensing and photographic techniques 966168 Using satellite imagery, CAD, and GPS to develop an environmental and engineering baseline J. M. Ellis & P. B. Goodwin, Earth Observation Magazine, 4(10), 1995, pp 16-18.