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Full-wave synthetic acoustic logs in radially semiinfinite saturated porous media
891138 Cyclic shear strength of a loose glacial till: note
Lefebvte, G; Malenfant, S Can Geotech J VZS. N2. May 1988. P401-407 The liquefaction potential of a silty sand (glacial till) was investigated using cyclic triaxial tests on saturated samples and constant volume cyclic simple shear tests on dry samples. The two materials showed very similar behaviour. and the 28% fines content appeared to offer no resistance to liquefaction. 891139 Response of a randomly inhomogeneous layer overlying a homogenous half space to surface harmonic excitation
Hryniewicz, Z; Hermans, A J Eurrhq Engng Struct Dynum Vl6. N.5, July 1988. P735-744
A harmonically loaded viscoelastic medium, with modulus of elasticity and density stationary random functions, overlying a homogeneous half space in considered, The method of Karal and Keller, based on the idea of fundamental matrix and the Bourret approximation, is employed. The equations derived are solved using the Laplace transform. By using boundary and continuity conditions, the mean wave solution is obtained. Correlation functions of the random medium, which introduce can be the source of wave long range interactions, amplification. 891140 Reflection characteristics of a mylonite zone based on compressional wave velocities of rock samples
McDonough, D T; Fountain, D M Geophys J V93. N3. June 1988. P547-558
Rock samples were taken from surface outcrops of the Kettle dome core complex, tonalitic gneiss containing a mylonite zone, regarded as a model for mid to deep crustal zones. Seismic wave velocities were measured at various confining pressures. Seismic anisotropy at low pressures is related to open microcracks and preferred mineral orientation, whilst the latter effect dominates at high pressures. Laboratory data were used as a basis to interpret reflections from the Kettle dome in regions where high and low velocity lithologies are interlayered. 891141 Velocity analysis of the SH-channel wave in the Schwalbach seam at Ensdorf colliery Cox, K B; Mason, I M Geophys Prospect V36, X3. April 1988. P298-317
Five different in-seam seismic velocity data analysers were applied to the data set from the Schwalbach seam, and results compared. The seam characteristics generally conform to those of the simplified model of Elsen et al (1985). Slight discrepancies could be removed by increasing the complexity of the model, but before this is done, the validity of the signal processing assumptions of seam isotropy and homogeneity must be tested.
equivalence is seen between the wave guide structures: homogeneous with varying seam thickness and horizontally inhomogeneous with constant seam thickness. 891143 Seismic and electric properties of unconsolidated permafrost
King, M S; Zimmerman,
R W; Co&n,
RF
Geophys Prospect V36. N4, May 1988. P349-364
A model has been developed to relate P and S wave velocities of permafrost, ideal&d as an assemblage of spherical quartz grains in a matrix of ice containing spherical inclusions of water, to porosity and extent of freezing of interstitial water. It predicts the velocities will fall as porosity or water to ice ratio increases. Laboratory measurements on core samples. which validate the theory, are described. 891144 Rorehole coupling of seismic waves in a permeable solid
White, J E; Welsh, E Geophys Prospect V36. N4. May 1988. P417-429
Expressions are derived for the acoustic pressure in a fluidfilled borehole due to the passage of plane compressional or shear waves propagating in a porous and permeable medium. The derivation is based on a quasistatic description, yielding results applicable at low frequencies. Computations for a plausible sandstone (with porosity of 0.21 and permeability of 300 millidarcies) show acoustic pressure to be a surprisingly distortion-free version of the stress waveform in a plane compressional wave. For a plane shear wave, the pressure waveform is visibly distorted. Auth. 891145 Effect of the aspect ratio on crack-induced anisotropy Douma, J Geophys Prospect V36. N6. Aug 1988. P614-632
Elastic wave propagation in media containing aligned cracks is analysed using a model valid for only small aspect ratios (Crampin) and one valid for all aspect ratios (Nishizawa). Elastic constants and group velocities are compared for both dry and fluid filled inclusions from flat cracks to spheres. The difference between models is small for aspect ratio up to 0.3, but becomes significant above this value. The simpler Crampin model is thus widely applicable. Anisotropy as a function of aspect ratio can be studied using Thomsen’s dimensionless parameters. 891146 Test methods for earthquake simulation in the geotechnical range (In German)
Klapperich, H; Savadis, S; Whitman, R V Geotechnik VII, N3. 1988, P133-141 A review of testing techniques, including field and model tests,
for earthquake simulation is presented, and the role of dynamic centrifuge testing and shaking table tests discussed. Two geotechnical problems dealing with soil liquefaction and soil structure interaction are outlined and results of testing are presented.
891142 Absorption-dir&n characteristics of channel waves propagating in coal seams of varying thickness
Dobroka, M Geophys Prospect V36. N3. April 1988. P318-331
The absorption-dispersion equations and displacement functions have been determined for Love seam waves in a three layered channel of varying thickness, using the WKB method. Phase and group velocity and absorption coefficient contain information on seam thickness variation, with maximum sensitivity to thickness variation around the Airy frequency. An
891147 Shear-wave velocity anisotropy in sedimentary rocks: a laboratory study
Rai, C S; Hanson, K E Geophysics VS3. N6. June 1988, P800-806
Systematic laboratory studies were carried out on limestone, sandstone, and shale samples under uniaxial and hydrostatic stress. Magnitude of observed anisotropy was dependent on rock lithology and magnitude and nature of the apphed stress. Shales showed significant anisotropy, independent of stress
:Q 1989 Pergamon Press plc. Reproduction
not permitted
19A regime, indicating preferentially orientated minerals. For sandstones, anisotropy was decreased by hydrostatic stress and increased by uniaxial stress, suggesting preferentially orientated cracks. Limestone showed weak velocity anisotropy. 891148 Full-wave synthetic acoustic logs in radially semiinflnite
saturated porous media Schmitt, D P; Bouchon, M; Bonnet, G Geophysics V53, N6. June 1988. P807-823 Useful information on in-situ properties of formations can be obtained from full waveform acoustic logs. Analysis of the effects of permeability,pore geometry, properties of the pore fluid, and borehole radius on the wave field generated by a point source in an axisymmetric fluid filled borehole in saturated rock has been attempted for wavebands corresponding to real data. Theoretical results are in good agreement with field observations and laboratory tests.
891152
Burst energy release index: tedmleai note Singh, S P Rock Meek Rock Engng V21, N2, April-June 1988, P149-155 Experiments to find a parameter which represents the energy released at the time of rock fracture, and which can be used as a relative measure of the burst proneness of rocks are presented. Energy released during failure in a soft testing machine was determined by seismogram readings of the extent of vibration generated in the machine. The vector sum of peak particle velocity of vibrations in vertical, longitudinal and transverse directions was used as a measure of energy released at fracture, and was termed Burst Energy Release Index (BERI). Burst proneness index was determined from elastic hysteresis loop parameters in uniaxial compression loading and unloading tests. Results for granite, norite and schist showed BERI may be useful as a relative measure to define burst proneness.
891149
Effects of contact line movement on the dissipation of waves in partially saturated rocks Miksis, M J J Geophys Res V93, NB6, June 198, P6624-6634 Attenuation of seismic waves in partially saturated rocks has been studied, with dissipation both due to fluid movement in the pores and contact (three phase) line movement being considered. Taking the latter into account can increase specific dissipation by an order of magnitude. This may account for differences between experiment and previous analyses. An exact solution for dissipation due to contact line movement in an inviscid fluid is presented.
891153 Dynamic reactions of composite soil medium
Chen, H T; Liu, M L Proc International Symposium o n Prediction and Performance in Geoteclmical Engineering, Calgary, 17-19 June 1987 P201206. Publ Rotterdam: A A Balkema, 1987 The dynamic behaviour of a massless cylindrical body of infinite length embedded in a composite soil medium consisting of a cylindrical inner zone surrounded by an infinite outer zone of superior mechanical properties has been analysed using plane strain 2-dimensional boundary element analysis. Results indicate that dynamic stiffness can be affected by whether or not the mass of the inner zone is included in the calculations.
891150
Penetration and liquefaction resistances: prior seismic history effects: technical note Seed, R B; Seung Rae Lee; Hsing-Lian Jong J Geotech Engng Div ASCE VII4. N6, June 1988. P691-697 Undrained cyclic triaxial tests on reconstituted samples of a fine sand were performed to establish the influence of prior seismic history in the material. Cone penetration tests in large scale triaxial samples of the same sand were undertaken to evaluate the influence of prior cyclic strains on cone penetration resistance. The tests show that prior seismic history increases liquefaction and cone-sleeve penetration resistance, but has no effect on cone-tip penetration resistance. This suggests that cone tip penetration resistance offers a conservative basis to evaluate liquefaction resistance of sandy soils with a prior seismic history.
891154 Study on the strain and pare water pressure characteristics of sandstone during repeated loading
Tien, Y M; Lee, D H; Juang, C H Key Questions in Rock Mecl~tics: Proc 29th US Symposium, Minneapolis, 13-15 June 1988 P43-49. Publ Rotterdam: A A Balkema, 1988 A series of quasi-static and repeated loading triaxial tests was
performed on a saturated sandstone. Results indicate that, for repeated loading, pore water pressure drops rapidly just before failure and that each specimen has a 'critical axial strain" after which failure occurs. This value is independent of confining pressure and loading frequency. A relation between axial strain and fatigue life of the specimen was established.
891151
Level ground soil-liquefaction analysis using in situ properties: II Arulanandan, K; Muraleetharan, K K J Geotech Engng Die ASCE VII4. N7, July 1988. P771-790 Methods for analysis of soil liquefaction are briefly reviewed and their shortcomings analysed. A new numerical procedure is proposed, based on a semi-empirical, one-dimensional elastoplastic constitutive model, and using the finite difference method to solve the governing differential equation for generation and dissipation of pore pressures, and settlement characteristics. A compressibility function is incorporated to account for soil properties at low effective stress. Centrifuge tests are used to verify the method. Input properties for the method can be obtained by a nondestructive electrical method.
891155
Soil liquefaction problems in recent Japanese earthquakes Yoshimi, Y Proc l lth International Conference on Soil Mechanics and Foundation Engineering, San Frcmcisco, 12-16 August 1985 VS, P2611-2616. Publ Rotterdam: A A Balkema, 1988 Damage caused by the Nihonkai-Chubu earthquake of 1983 is discussed. The main cause was widespread liquefaction of alluvial and reclaimed sands. Light structures were severely damaged, large sand craters due to sand boil were observed, and liquefaction during aftershocks was seen. Possible preventative or mitigative measures are briefly discussed.
1989 Pergamon Press plc. Reproduction not permitted
Lefebvte, G; Malenfant, S Can Geotech J VZS. N2. May 1988. P401-407 The liquefaction potential of a silty sand (glacial till) was investigated using cyclic triaxial tests on saturated samples and constant volume cyclic simple shear tests on dry samples. The two materials showed very similar behaviour. and the 28% fines content appeared to offer no resistance to liquefaction. 891139 Response of a randomly inhomogeneous layer overlying a homogenous half space to surface harmonic excitation
Hryniewicz, Z; Hermans, A J Eurrhq Engng Struct Dynum Vl6. N.5, July 1988. P735-744
A harmonically loaded viscoelastic medium, with modulus of elasticity and density stationary random functions, overlying a homogeneous half space in considered, The method of Karal and Keller, based on the idea of fundamental matrix and the Bourret approximation, is employed. The equations derived are solved using the Laplace transform. By using boundary and continuity conditions, the mean wave solution is obtained. Correlation functions of the random medium, which introduce can be the source of wave long range interactions, amplification. 891140 Reflection characteristics of a mylonite zone based on compressional wave velocities of rock samples
McDonough, D T; Fountain, D M Geophys J V93. N3. June 1988. P547-558
Rock samples were taken from surface outcrops of the Kettle dome core complex, tonalitic gneiss containing a mylonite zone, regarded as a model for mid to deep crustal zones. Seismic wave velocities were measured at various confining pressures. Seismic anisotropy at low pressures is related to open microcracks and preferred mineral orientation, whilst the latter effect dominates at high pressures. Laboratory data were used as a basis to interpret reflections from the Kettle dome in regions where high and low velocity lithologies are interlayered. 891141 Velocity analysis of the SH-channel wave in the Schwalbach seam at Ensdorf colliery Cox, K B; Mason, I M Geophys Prospect V36, X3. April 1988. P298-317
Five different in-seam seismic velocity data analysers were applied to the data set from the Schwalbach seam, and results compared. The seam characteristics generally conform to those of the simplified model of Elsen et al (1985). Slight discrepancies could be removed by increasing the complexity of the model, but before this is done, the validity of the signal processing assumptions of seam isotropy and homogeneity must be tested.
equivalence is seen between the wave guide structures: homogeneous with varying seam thickness and horizontally inhomogeneous with constant seam thickness. 891143 Seismic and electric properties of unconsolidated permafrost
King, M S; Zimmerman,
R W; Co&n,
RF
Geophys Prospect V36. N4, May 1988. P349-364
A model has been developed to relate P and S wave velocities of permafrost, ideal&d as an assemblage of spherical quartz grains in a matrix of ice containing spherical inclusions of water, to porosity and extent of freezing of interstitial water. It predicts the velocities will fall as porosity or water to ice ratio increases. Laboratory measurements on core samples. which validate the theory, are described. 891144 Rorehole coupling of seismic waves in a permeable solid
White, J E; Welsh, E Geophys Prospect V36. N4. May 1988. P417-429
Expressions are derived for the acoustic pressure in a fluidfilled borehole due to the passage of plane compressional or shear waves propagating in a porous and permeable medium. The derivation is based on a quasistatic description, yielding results applicable at low frequencies. Computations for a plausible sandstone (with porosity of 0.21 and permeability of 300 millidarcies) show acoustic pressure to be a surprisingly distortion-free version of the stress waveform in a plane compressional wave. For a plane shear wave, the pressure waveform is visibly distorted. Auth. 891145 Effect of the aspect ratio on crack-induced anisotropy Douma, J Geophys Prospect V36. N6. Aug 1988. P614-632
Elastic wave propagation in media containing aligned cracks is analysed using a model valid for only small aspect ratios (Crampin) and one valid for all aspect ratios (Nishizawa). Elastic constants and group velocities are compared for both dry and fluid filled inclusions from flat cracks to spheres. The difference between models is small for aspect ratio up to 0.3, but becomes significant above this value. The simpler Crampin model is thus widely applicable. Anisotropy as a function of aspect ratio can be studied using Thomsen’s dimensionless parameters. 891146 Test methods for earthquake simulation in the geotechnical range (In German)
Klapperich, H; Savadis, S; Whitman, R V Geotechnik VII, N3. 1988, P133-141 A review of testing techniques, including field and model tests,
for earthquake simulation is presented, and the role of dynamic centrifuge testing and shaking table tests discussed. Two geotechnical problems dealing with soil liquefaction and soil structure interaction are outlined and results of testing are presented.
891142 Absorption-dir&n characteristics of channel waves propagating in coal seams of varying thickness
Dobroka, M Geophys Prospect V36. N3. April 1988. P318-331
The absorption-dispersion equations and displacement functions have been determined for Love seam waves in a three layered channel of varying thickness, using the WKB method. Phase and group velocity and absorption coefficient contain information on seam thickness variation, with maximum sensitivity to thickness variation around the Airy frequency. An
891147 Shear-wave velocity anisotropy in sedimentary rocks: a laboratory study
Rai, C S; Hanson, K E Geophysics VS3. N6. June 1988, P800-806
Systematic laboratory studies were carried out on limestone, sandstone, and shale samples under uniaxial and hydrostatic stress. Magnitude of observed anisotropy was dependent on rock lithology and magnitude and nature of the apphed stress. Shales showed significant anisotropy, independent of stress
:Q 1989 Pergamon Press plc. Reproduction
not permitted
19A regime, indicating preferentially orientated minerals. For sandstones, anisotropy was decreased by hydrostatic stress and increased by uniaxial stress, suggesting preferentially orientated cracks. Limestone showed weak velocity anisotropy. 891148 Full-wave synthetic acoustic logs in radially semiinflnite
saturated porous media Schmitt, D P; Bouchon, M; Bonnet, G Geophysics V53, N6. June 1988. P807-823 Useful information on in-situ properties of formations can be obtained from full waveform acoustic logs. Analysis of the effects of permeability,pore geometry, properties of the pore fluid, and borehole radius on the wave field generated by a point source in an axisymmetric fluid filled borehole in saturated rock has been attempted for wavebands corresponding to real data. Theoretical results are in good agreement with field observations and laboratory tests.
891152
Burst energy release index: tedmleai note Singh, S P Rock Meek Rock Engng V21, N2, April-June 1988, P149-155 Experiments to find a parameter which represents the energy released at the time of rock fracture, and which can be used as a relative measure of the burst proneness of rocks are presented. Energy released during failure in a soft testing machine was determined by seismogram readings of the extent of vibration generated in the machine. The vector sum of peak particle velocity of vibrations in vertical, longitudinal and transverse directions was used as a measure of energy released at fracture, and was termed Burst Energy Release Index (BERI). Burst proneness index was determined from elastic hysteresis loop parameters in uniaxial compression loading and unloading tests. Results for granite, norite and schist showed BERI may be useful as a relative measure to define burst proneness.
891149
Effects of contact line movement on the dissipation of waves in partially saturated rocks Miksis, M J J Geophys Res V93, NB6, June 198, P6624-6634 Attenuation of seismic waves in partially saturated rocks has been studied, with dissipation both due to fluid movement in the pores and contact (three phase) line movement being considered. Taking the latter into account can increase specific dissipation by an order of magnitude. This may account for differences between experiment and previous analyses. An exact solution for dissipation due to contact line movement in an inviscid fluid is presented.
891153 Dynamic reactions of composite soil medium
Chen, H T; Liu, M L Proc International Symposium o n Prediction and Performance in Geoteclmical Engineering, Calgary, 17-19 June 1987 P201206. Publ Rotterdam: A A Balkema, 1987 The dynamic behaviour of a massless cylindrical body of infinite length embedded in a composite soil medium consisting of a cylindrical inner zone surrounded by an infinite outer zone of superior mechanical properties has been analysed using plane strain 2-dimensional boundary element analysis. Results indicate that dynamic stiffness can be affected by whether or not the mass of the inner zone is included in the calculations.
891150
Penetration and liquefaction resistances: prior seismic history effects: technical note Seed, R B; Seung Rae Lee; Hsing-Lian Jong J Geotech Engng Div ASCE VII4. N6, June 1988. P691-697 Undrained cyclic triaxial tests on reconstituted samples of a fine sand were performed to establish the influence of prior seismic history in the material. Cone penetration tests in large scale triaxial samples of the same sand were undertaken to evaluate the influence of prior cyclic strains on cone penetration resistance. The tests show that prior seismic history increases liquefaction and cone-sleeve penetration resistance, but has no effect on cone-tip penetration resistance. This suggests that cone tip penetration resistance offers a conservative basis to evaluate liquefaction resistance of sandy soils with a prior seismic history.
891154 Study on the strain and pare water pressure characteristics of sandstone during repeated loading
Tien, Y M; Lee, D H; Juang, C H Key Questions in Rock Mecl~tics: Proc 29th US Symposium, Minneapolis, 13-15 June 1988 P43-49. Publ Rotterdam: A A Balkema, 1988 A series of quasi-static and repeated loading triaxial tests was
performed on a saturated sandstone. Results indicate that, for repeated loading, pore water pressure drops rapidly just before failure and that each specimen has a 'critical axial strain" after which failure occurs. This value is independent of confining pressure and loading frequency. A relation between axial strain and fatigue life of the specimen was established.
891151
Level ground soil-liquefaction analysis using in situ properties: II Arulanandan, K; Muraleetharan, K K J Geotech Engng Die ASCE VII4. N7, July 1988. P771-790 Methods for analysis of soil liquefaction are briefly reviewed and their shortcomings analysed. A new numerical procedure is proposed, based on a semi-empirical, one-dimensional elastoplastic constitutive model, and using the finite difference method to solve the governing differential equation for generation and dissipation of pore pressures, and settlement characteristics. A compressibility function is incorporated to account for soil properties at low effective stress. Centrifuge tests are used to verify the method. Input properties for the method can be obtained by a nondestructive electrical method.
891155
Soil liquefaction problems in recent Japanese earthquakes Yoshimi, Y Proc l lth International Conference on Soil Mechanics and Foundation Engineering, San Frcmcisco, 12-16 August 1985 VS, P2611-2616. Publ Rotterdam: A A Balkema, 1988 Damage caused by the Nihonkai-Chubu earthquake of 1983 is discussed. The main cause was widespread liquefaction of alluvial and reclaimed sands. Light structures were severely damaged, large sand craters due to sand boil were observed, and liquefaction during aftershocks was seen. Possible preventative or mitigative measures are briefly discussed.
1989 Pergamon Press plc. Reproduction not permitted