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Estimates of velocity dispersion between seismic and ultrasonic frequencies
183A 865106 Consolidation of soils under static or dynamic loading Qian, J H Proc 5th International Conference on Numerical Methods in Geomechanics, Nagoya. 1-5 April 1985 VI. PI05-110. Publ Rotterdam: A. ,4. Balkema, 1985 The theory of consolidation of soil is examined in two parts, One is the consolidation of soils under static or slowly varying load, the other being the consolidation of soils under dynamic or repeated transient loading. This is a brief summary of research work during the last two decades, including some related research results from other institutions in China and foreign countries. Both parts contain some mathematical and numerical treatments, laboratory tests, field measurements, explanation of internal mechanisms and applications to engineering projects.
Dynamic properties
Analysis of seismic data involved determining interval velocities from stacking velocities, calculating layer thicknesses, and then comparing layer thicknesses from S-wave data with thicknesses from P-wave data. It was concluded that when the Swave thicknesses were significantly greater than the P-wave, the layer was anisotropic. 865110 Acoustic relaxation in sedimentary rocks: Dependence on grain contacts and fluid saturation Murphy, W F; Winkler. K W; Kleinberg, R L Geophysics VI5. N3. March 1986, P757-766 Partial fluid saturation affects absorption and dispersion in sandstones. The proposed theoretical model describes acoustic relaxation due to local fluid flow. It is based upon observed microstructures in sandstones. The model predicts the real and imaginary parts of the complex frame moduli as a function of frequency and fluid saturation. The theoretical results are compared to experimental observations.
See also: 865178 865 ! 07 Experimental determination of elastic anisotropy of Berea sandstone, Chieopee shale, and Chelmsford granite Lo, T W; Coyner, K B; Toksoz, M N Geophysics V5. NI. Jan 1986. P164-171 The ultrasonic transmission method is used to measure P-, SH-and SV-wavc velocities for Chclmsford granite, Chicopee shale, and Bcrea sandstone in different directions, at up to 1000 bars confining pressure, The velocity measurements indicate these three rocks are elastically anisotropic. The stiffness constants, dynamic Young's moduli, dynamic Poisson's ratios, and dynamic bulk moduli of the three rocks were also calculated. The elastic constants, together with velocity measurements, suggest that: (I) elastic anisotropy is due to the combined effects of pores or cracks and mineral grain orientation, and (2) elastic anisotropy decreases with increasing confining pressure. The residual anisotropy at higher confining pressure is due to mineral grain orientation. Auth. 865108 Estimates of velocity dispersion between seismic and ultrasonic frequencies Winkler, K W Geophysics 1/51, NI, Jan 1986, P183-189 A simple analysis technique that gives estimates of total velocity dispersion between zero frequency and any measurement frequency is presented. It is applied to a variety of data from the literature. Dispersion estimates are computed for different rocks, different pore fluids, and different degrees of saturation. The results provide estimated upper bounds on the amount of velocity dispersion observable in the field and also consistent support for the presence of an absorption dispersion mechanism involving local flow of pore fluid. 865109 Anisotropy effects in P-wave and SH-wave stacking velocities contain information on lithology Winterstein, D F Geophysics V51, N3, March 1986. P661-672 The magnitude of anisotropy effects in S wave data is documented. Instances where anisotropy effects originated in intrinsic rock properties rather than in layering are presented.
865 ! I I Estimating liquefaction potential of sands using the fiat plate dilatometer. Technical note Robertson, P K; Campanella, R G Geotech Test J vg, NI, March 1986, P38-40 A new fiat plate dilatometer test (DMT) based method for liquefaction assessment of sands is presented. Field and laboratory data from a site near Vancouver, Canada. are used to provide a preliminary assessment of its usefulness. 865112 Dynamic stability analysis of undrained simple shear on watersaturated granular soils Vardoulakis. I Int J Num Anal Meth Geomech VIO. N2, March-April 1986, P177-190 Dynamic stability of undrained, simple-shear deformations on water-saturated granular soil specimens is discussed. The soil is described by a 2D-flow theory of plasticity for frictional and dilatant material. Contractant material becomes unstable (liquifies) at the state of maximum shear stress, whereas dilatant material becomes unstable after the state of maximum effective stress obliquity is reached in the softening regime of the background drained behaviour. In both cases the correct evolution equations for the growth coefficient of the instability are derived and compared with the results of the inertia-free formulation of the problem. Auth. 865113 Influence of soil layer with disturbed boundary zone. Technical note Veletsos, A S; Dotson, K W J Geotech Engng Div ASCE VII2, N3, March 1986, P363368 The dynamic impedances of a vertically and torsionally excited viscoelastic soil layer with a thin disturbed zone around the edge of a central circular hole have been evaluated and compared, over a range of parameters, with those obtained by a previously proposed, simpler analysis in which the mass of the disturbed zone is neglected. It has been shown that the results of the two approaches may differ significantly, and that the simpler solution should be used with the greatest possible care. Auth.
© 1986 Pergamon Journals Ltd. Reproduction not permitted
Dynamic properties
Analysis of seismic data involved determining interval velocities from stacking velocities, calculating layer thicknesses, and then comparing layer thicknesses from S-wave data with thicknesses from P-wave data. It was concluded that when the Swave thicknesses were significantly greater than the P-wave, the layer was anisotropic. 865110 Acoustic relaxation in sedimentary rocks: Dependence on grain contacts and fluid saturation Murphy, W F; Winkler. K W; Kleinberg, R L Geophysics VI5. N3. March 1986, P757-766 Partial fluid saturation affects absorption and dispersion in sandstones. The proposed theoretical model describes acoustic relaxation due to local fluid flow. It is based upon observed microstructures in sandstones. The model predicts the real and imaginary parts of the complex frame moduli as a function of frequency and fluid saturation. The theoretical results are compared to experimental observations.
See also: 865178 865 ! 07 Experimental determination of elastic anisotropy of Berea sandstone, Chieopee shale, and Chelmsford granite Lo, T W; Coyner, K B; Toksoz, M N Geophysics V5. NI. Jan 1986. P164-171 The ultrasonic transmission method is used to measure P-, SH-and SV-wavc velocities for Chclmsford granite, Chicopee shale, and Bcrea sandstone in different directions, at up to 1000 bars confining pressure, The velocity measurements indicate these three rocks are elastically anisotropic. The stiffness constants, dynamic Young's moduli, dynamic Poisson's ratios, and dynamic bulk moduli of the three rocks were also calculated. The elastic constants, together with velocity measurements, suggest that: (I) elastic anisotropy is due to the combined effects of pores or cracks and mineral grain orientation, and (2) elastic anisotropy decreases with increasing confining pressure. The residual anisotropy at higher confining pressure is due to mineral grain orientation. Auth. 865108 Estimates of velocity dispersion between seismic and ultrasonic frequencies Winkler, K W Geophysics 1/51, NI, Jan 1986, P183-189 A simple analysis technique that gives estimates of total velocity dispersion between zero frequency and any measurement frequency is presented. It is applied to a variety of data from the literature. Dispersion estimates are computed for different rocks, different pore fluids, and different degrees of saturation. The results provide estimated upper bounds on the amount of velocity dispersion observable in the field and also consistent support for the presence of an absorption dispersion mechanism involving local flow of pore fluid. 865109 Anisotropy effects in P-wave and SH-wave stacking velocities contain information on lithology Winterstein, D F Geophysics V51, N3, March 1986. P661-672 The magnitude of anisotropy effects in S wave data is documented. Instances where anisotropy effects originated in intrinsic rock properties rather than in layering are presented.
865 ! I I Estimating liquefaction potential of sands using the fiat plate dilatometer. Technical note Robertson, P K; Campanella, R G Geotech Test J vg, NI, March 1986, P38-40 A new fiat plate dilatometer test (DMT) based method for liquefaction assessment of sands is presented. Field and laboratory data from a site near Vancouver, Canada. are used to provide a preliminary assessment of its usefulness. 865112 Dynamic stability analysis of undrained simple shear on watersaturated granular soils Vardoulakis. I Int J Num Anal Meth Geomech VIO. N2, March-April 1986, P177-190 Dynamic stability of undrained, simple-shear deformations on water-saturated granular soil specimens is discussed. The soil is described by a 2D-flow theory of plasticity for frictional and dilatant material. Contractant material becomes unstable (liquifies) at the state of maximum shear stress, whereas dilatant material becomes unstable after the state of maximum effective stress obliquity is reached in the softening regime of the background drained behaviour. In both cases the correct evolution equations for the growth coefficient of the instability are derived and compared with the results of the inertia-free formulation of the problem. Auth. 865113 Influence of soil layer with disturbed boundary zone. Technical note Veletsos, A S; Dotson, K W J Geotech Engng Div ASCE VII2, N3, March 1986, P363368 The dynamic impedances of a vertically and torsionally excited viscoelastic soil layer with a thin disturbed zone around the edge of a central circular hole have been evaluated and compared, over a range of parameters, with those obtained by a previously proposed, simpler analysis in which the mass of the disturbed zone is neglected. It has been shown that the results of the two approaches may differ significantly, and that the simpler solution should be used with the greatest possible care. Auth.
© 1986 Pergamon Journals Ltd. Reproduction not permitted