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Measuring pore water pressures in the subsoil
367A
Monitoring rock and soil mass performance
Rock block analysis
See also." 916021, 916411, 916484
916291 Predictions of block size distribution for quarrying Wang, H; Latham, J P; Poole, A B Q J Engng Geol V24, N1, 1991, P91-99. (paper to the conference on Geological Materials in Construction, London, November 1989)
916288 Frequency response problems to instrumented pile tests Poskitt, T J; Yip-Wong, K L Ground Engng V24, N4, May 1991, P28-39 Results from a series of tests on two fully instrumented large diameter piles are presented, and critical aspects of the design and selection of the transducers discussed. The most severe conditions occur during driving, when passage of stress waves through the pile causes vigorous motion of the instrumentation and its fixings. Natural frequency and damping are shown to be critical under these conditions. Major problems can occur with accelerometers. During re-driving, the signal:noise ratio falls significantly. It is recommended that for routine dynamic pile testing, raw data be plotted in the frequency domain to prevent masking due to signal conditioning.
916289 Application of photogrammetric techniques in assessing underground mine opening deformations and stability Eichfeld, W; Ono, E; Chugh, Y P; Chert, G Rock Mechanics Contributions and Challenges: Proc 31st US Symposium, Golden, 18-20 June 1990 P587-594. Publ Rotterdam: A A Balkema, 1990 An attempt to develop a photogrammetric technique for fast, accurate, and economic monitoring of mine entry deformation to an accuracy of 2.5mm is presented. Choice of equipment, work with a laboratory scale model, in-mine use, and data reduction are described. Possible sources of errors and illumination problems and their solutions are discussed.
916290 Measuring pore water pressures in the subsoil Kohler, H J; Heibaum, M H Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 V2, P1193-1198. Publ Rotterdam: A A Balkema, 1990 Design and installation of instrumentation to monitor pore pressure in the subsoil, in particular dam foundations, are described. Pressure transducers are installed and sealed using special packers in steel tubes which can be driven to the desired depth at any stage during the construction procedure. Data collection and storage can be by microprocessor controlled equipment. The system can be easily installed and has proved reliable.
Analysis Techniques and Design Methods See: 916179, 916472
A new method to predict the in situ block size distribution and block shape for a discontinuous rock mass is presented. Detailed field discontinuity mapping is the first stage. Following preliminary data analysis, an algorithm based principally on the block theory of Goodman and Shi is used to determine block sizes and shapes. Applications to simulated and natural discontinuity data are illustrated. Limitations are discussed.
Stress analysis See also: 916103, 916108, 916109, 916502 916292 Combined hardening model of anisotropicaliy consolidated cohesive soils Hirai, H; Kamei, T Can Geotech J V28, N1, Feb 1991, PI-IO A constitutive model is proposed which has the following features: yield function and plastic potential are described by generalised forms of the Cam clay model; a combination of isotropic and kinematic hardening; non-associated flow; isotropic hardening involves plastic work associated with both volumetric change and deviatoric deformation; and Zeigler's rule of kinematic hardening used to specify translation of the yield surface. The model can describe expansion, translation, and rotation of the yield surface in stress space. Good agreement is seen between model predictions and results of undrained triaxial tests on anisotropically consolidated cohesive soils. 916293 Selection of operative centrifuge radius to minimise stress error in calculations. Note Cooke, B Can Geotech J V28, NI, Feb 1991, P160-161 In the geotechnical centrifuge, vertical stress distribution is nonlinear,as the 'gravity' field varies with centrifuge radius from top to bottom of the model. When calculating centrifugal acceleration (and thus scale of the model) care must be taken to define a centrifuge radius which minimises stress error in the model. It is demonstrated that optimum radius is measured from the centre of rotation to a point 0.59 times the model height from the centre of the model. 916294 Comprehensive review of strain localization in elastoplastic soils Bardet, J P Comput Geotech VIO, N3, 1990, P163-188 The theory of strain localisation for elastoplastic soils is reviewed and examined in relation to published work on the inclination of shear bands. Experimental results and theoretical predictions of shear band orientation are compared. Effects of elastic unloading and influences of friction angle, dilatancy, Poisson's ratio, and hardening modulus on shear bands are discussed. The theory is applied to Mohr-Coulomb and Drucker-Prager soils, and it is seen that it accounts for
© 1991 Pergamon Press plc. Reproduction not permitted
Monitoring rock and soil mass performance
Rock block analysis
See also." 916021, 916411, 916484
916291 Predictions of block size distribution for quarrying Wang, H; Latham, J P; Poole, A B Q J Engng Geol V24, N1, 1991, P91-99. (paper to the conference on Geological Materials in Construction, London, November 1989)
916288 Frequency response problems to instrumented pile tests Poskitt, T J; Yip-Wong, K L Ground Engng V24, N4, May 1991, P28-39 Results from a series of tests on two fully instrumented large diameter piles are presented, and critical aspects of the design and selection of the transducers discussed. The most severe conditions occur during driving, when passage of stress waves through the pile causes vigorous motion of the instrumentation and its fixings. Natural frequency and damping are shown to be critical under these conditions. Major problems can occur with accelerometers. During re-driving, the signal:noise ratio falls significantly. It is recommended that for routine dynamic pile testing, raw data be plotted in the frequency domain to prevent masking due to signal conditioning.
916289 Application of photogrammetric techniques in assessing underground mine opening deformations and stability Eichfeld, W; Ono, E; Chugh, Y P; Chert, G Rock Mechanics Contributions and Challenges: Proc 31st US Symposium, Golden, 18-20 June 1990 P587-594. Publ Rotterdam: A A Balkema, 1990 An attempt to develop a photogrammetric technique for fast, accurate, and economic monitoring of mine entry deformation to an accuracy of 2.5mm is presented. Choice of equipment, work with a laboratory scale model, in-mine use, and data reduction are described. Possible sources of errors and illumination problems and their solutions are discussed.
916290 Measuring pore water pressures in the subsoil Kohler, H J; Heibaum, M H Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 V2, P1193-1198. Publ Rotterdam: A A Balkema, 1990 Design and installation of instrumentation to monitor pore pressure in the subsoil, in particular dam foundations, are described. Pressure transducers are installed and sealed using special packers in steel tubes which can be driven to the desired depth at any stage during the construction procedure. Data collection and storage can be by microprocessor controlled equipment. The system can be easily installed and has proved reliable.
Analysis Techniques and Design Methods See: 916179, 916472
A new method to predict the in situ block size distribution and block shape for a discontinuous rock mass is presented. Detailed field discontinuity mapping is the first stage. Following preliminary data analysis, an algorithm based principally on the block theory of Goodman and Shi is used to determine block sizes and shapes. Applications to simulated and natural discontinuity data are illustrated. Limitations are discussed.
Stress analysis See also: 916103, 916108, 916109, 916502 916292 Combined hardening model of anisotropicaliy consolidated cohesive soils Hirai, H; Kamei, T Can Geotech J V28, N1, Feb 1991, PI-IO A constitutive model is proposed which has the following features: yield function and plastic potential are described by generalised forms of the Cam clay model; a combination of isotropic and kinematic hardening; non-associated flow; isotropic hardening involves plastic work associated with both volumetric change and deviatoric deformation; and Zeigler's rule of kinematic hardening used to specify translation of the yield surface. The model can describe expansion, translation, and rotation of the yield surface in stress space. Good agreement is seen between model predictions and results of undrained triaxial tests on anisotropically consolidated cohesive soils. 916293 Selection of operative centrifuge radius to minimise stress error in calculations. Note Cooke, B Can Geotech J V28, NI, Feb 1991, P160-161 In the geotechnical centrifuge, vertical stress distribution is nonlinear,as the 'gravity' field varies with centrifuge radius from top to bottom of the model. When calculating centrifugal acceleration (and thus scale of the model) care must be taken to define a centrifuge radius which minimises stress error in the model. It is demonstrated that optimum radius is measured from the centre of rotation to a point 0.59 times the model height from the centre of the model. 916294 Comprehensive review of strain localization in elastoplastic soils Bardet, J P Comput Geotech VIO, N3, 1990, P163-188 The theory of strain localisation for elastoplastic soils is reviewed and examined in relation to published work on the inclination of shear bands. Experimental results and theoretical predictions of shear band orientation are compared. Effects of elastic unloading and influences of friction angle, dilatancy, Poisson's ratio, and hardening modulus on shear bands are discussed. The theory is applied to Mohr-Coulomb and Drucker-Prager soils, and it is seen that it accounts for
© 1991 Pergamon Press plc. Reproduction not permitted