The Experts below are selected from a list of 13146 Experts worldwide ranked by ideXlab platform
Masayoshi Sato - One of the best experts on this subject based on the ideXlab platform.
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Effects of air bubbles on B-value and P-wave velocity of a partly Saturated Sand
SOILS AND FOUNDATIONS, 2002Co-Authors: Shuji Tamura, Kohji Tokimatsu, Akio Abe, Masayoshi SatoAbstract:ABSTRACT The effects of the size and solubility of an air bubble on the B-value and P-wave velocity of a partly Saturated Sand are discussed. The relations between B-value and P-wave velocity are determined for large triaxial specimens with Dr = 64% and 84%. Theoretical formulas have been derived for determining the P-wave velocity of a partly Saturated Sand containing air bubbles. It is shown that: (1) the solubility of air bubbles in the pore-water significantly affects the relations between B-value and P-wave velocity; (2) the practical coefficient of solubility of air bubble pressured in the pore-water is about 0.002; (3) the B-value and P-wave velocity increase with a decrease in the air bubble size. This tendency is significant, when the diameter of the air bubble is less than about 0.005 mm.
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Simplified Estimation of Earthquake-Induced Settlements in Saturated Sand Deposits
Soils and Foundations, 1996Co-Authors: Yasuhiro Shamoto, Masayoshi Sato, Jian-min ZhangAbstract:ABSTRACT This study presents a simplified method for estimating earthquake-induced settlements of Saturated Sand deposits based on previously available studies and undrained cyclic loading tests followed by drained reconsolidation under non-zero or zero lateral strains for various Sands. It has been shown that: (1) the volume change of different Sands over a wide density range can be uniquely related to “relative compression” as defined by ∆ e/(ei – emin); (2) the total volumetric strain of Saturated Sand is not obviously influenced by a swelling history following undrained cyclic loading; and (3) the volumetric strain after undrained cyclic loading is not significantly affected by the boundary constraint of non-zero or zero lateral strains. It has been found that the relationship between the logarithm of the relative compression after complete or incomplete liquefaction and the logarithm of the maximum shear strain induced during preceding undrained cyclic loading is approximately linear over a range of maximum shear strain from 0.01% to 10% and of relative densities from 20% to 90% for five Sands under non-zero or zero lateral strain conditions. The results predicted by the proposed method compare favorably with experimental observations of shaking table tests on Saturated Sand in a laminar container. The proposed method may therefore be used as a first approximation for estimating earthquake-induced settlements of Saturated Sand deposits.
Yasuhiro Shamoto - One of the best experts on this subject based on the ideXlab platform.
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MECHANISM OF LARGE POST-LIQUEFACTION DEFORMATION IN Saturated Sand
Soils and Foundations, 1997Co-Authors: Yasuhiro Shamoto, Jian-min Zhang, Goto ShigeruAbstract:ABSTRACT A new mechanism of large post-liquefaction shear deformation in Saturated Sand was established on the physical basis that the shear deformation is governed by two types of volumetric strains due to dilatancy, i.e., an irreversible dilatancy component, ɛv.ir, and a reversible dilatancy component, ɛv,re. It was found that: 1) the shear strain is composed of a shear strain component depending on change in effective stress γd, and a shear strain component independent of effective stress γo; 2) post-liquefaction γo-value is triggered principally in the state of zero effective confining stress, and its current magnitude has a nearly unique relationship with the preceding maximum shear strain γmax for Sand of a given density; and 3) γd is determined by a good correlation existing between dɛv.rel/dγd and deviator-isotropic stress ratio, q/p'. Based on the formulation for the above experimental findings and stress-dilatancy concept, a new approach is proposed to evaluate the large post-liquefaction shear strain y =(γo + γd) in Saturated Sand. The results predicted by the proposed method compared favorably with experimental observation.
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Simplified Estimation of Earthquake-Induced Settlements in Saturated Sand Deposits
Soils and Foundations, 1996Co-Authors: Yasuhiro Shamoto, Masayoshi Sato, Jian-min ZhangAbstract:ABSTRACT This study presents a simplified method for estimating earthquake-induced settlements of Saturated Sand deposits based on previously available studies and undrained cyclic loading tests followed by drained reconsolidation under non-zero or zero lateral strains for various Sands. It has been shown that: (1) the volume change of different Sands over a wide density range can be uniquely related to “relative compression” as defined by ∆ e/(ei – emin); (2) the total volumetric strain of Saturated Sand is not obviously influenced by a swelling history following undrained cyclic loading; and (3) the volumetric strain after undrained cyclic loading is not significantly affected by the boundary constraint of non-zero or zero lateral strains. It has been found that the relationship between the logarithm of the relative compression after complete or incomplete liquefaction and the logarithm of the maximum shear strain induced during preceding undrained cyclic loading is approximately linear over a range of maximum shear strain from 0.01% to 10% and of relative densities from 20% to 90% for five Sands under non-zero or zero lateral strain conditions. The results predicted by the proposed method compare favorably with experimental observations of shaking table tests on Saturated Sand in a laminar container. The proposed method may therefore be used as a first approximation for estimating earthquake-induced settlements of Saturated Sand deposits.
P Foray - One of the best experts on this subject based on the ideXlab platform.
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Laboratory P-wave measurements in dry and Saturated Sand
Acta Geotechnica, 2006Co-Authors: Mark Emerson, P ForayAbstract:We measure the P-wave velocity in a clean medium Sand subject to very low stress in a large-scale laboratory cross-hole experiment for frequencies less than 10 kHz. In dry Sand the velocity is depth-, and therefore, stress-dependent according to a power law. The velocity in partially Saturated Sand is essentially the same as in dry Sand, which confirms the analytical result of the Biot–Gassmann theory. At 100% satura- tion, the velocity largely exceeds that in dry and par- tially Saturated Sand, once again in accordance with the Biot–Gassmann theory. However, the theory under- predicts velocities by up to 12% in some cases at full saturation. The maximum attenuation determined from spectral analysis of the measured signals closely matches the characteristic frequency predicted by the Biot model.
Goto Shigeru - One of the best experts on this subject based on the ideXlab platform.
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MECHANISM OF LARGE POST-LIQUEFACTION DEFORMATION IN Saturated Sand
Soils and Foundations, 1997Co-Authors: Yasuhiro Shamoto, Jian-min Zhang, Goto ShigeruAbstract:ABSTRACT A new mechanism of large post-liquefaction shear deformation in Saturated Sand was established on the physical basis that the shear deformation is governed by two types of volumetric strains due to dilatancy, i.e., an irreversible dilatancy component, ɛv.ir, and a reversible dilatancy component, ɛv,re. It was found that: 1) the shear strain is composed of a shear strain component depending on change in effective stress γd, and a shear strain component independent of effective stress γo; 2) post-liquefaction γo-value is triggered principally in the state of zero effective confining stress, and its current magnitude has a nearly unique relationship with the preceding maximum shear strain γmax for Sand of a given density; and 3) γd is determined by a good correlation existing between dɛv.rel/dγd and deviator-isotropic stress ratio, q/p'. Based on the formulation for the above experimental findings and stress-dilatancy concept, a new approach is proposed to evaluate the large post-liquefaction shear strain y =(γo + γd) in Saturated Sand. The results predicted by the proposed method compared favorably with experimental observation.
Jian-min Zhang - One of the best experts on this subject based on the ideXlab platform.
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MECHANISM OF LARGE POST-LIQUEFACTION DEFORMATION IN Saturated Sand
Soils and Foundations, 1997Co-Authors: Yasuhiro Shamoto, Jian-min Zhang, Goto ShigeruAbstract:ABSTRACT A new mechanism of large post-liquefaction shear deformation in Saturated Sand was established on the physical basis that the shear deformation is governed by two types of volumetric strains due to dilatancy, i.e., an irreversible dilatancy component, ɛv.ir, and a reversible dilatancy component, ɛv,re. It was found that: 1) the shear strain is composed of a shear strain component depending on change in effective stress γd, and a shear strain component independent of effective stress γo; 2) post-liquefaction γo-value is triggered principally in the state of zero effective confining stress, and its current magnitude has a nearly unique relationship with the preceding maximum shear strain γmax for Sand of a given density; and 3) γd is determined by a good correlation existing between dɛv.rel/dγd and deviator-isotropic stress ratio, q/p'. Based on the formulation for the above experimental findings and stress-dilatancy concept, a new approach is proposed to evaluate the large post-liquefaction shear strain y =(γo + γd) in Saturated Sand. The results predicted by the proposed method compared favorably with experimental observation.
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Simplified Estimation of Earthquake-Induced Settlements in Saturated Sand Deposits
Soils and Foundations, 1996Co-Authors: Yasuhiro Shamoto, Masayoshi Sato, Jian-min ZhangAbstract:ABSTRACT This study presents a simplified method for estimating earthquake-induced settlements of Saturated Sand deposits based on previously available studies and undrained cyclic loading tests followed by drained reconsolidation under non-zero or zero lateral strains for various Sands. It has been shown that: (1) the volume change of different Sands over a wide density range can be uniquely related to “relative compression” as defined by ∆ e/(ei – emin); (2) the total volumetric strain of Saturated Sand is not obviously influenced by a swelling history following undrained cyclic loading; and (3) the volumetric strain after undrained cyclic loading is not significantly affected by the boundary constraint of non-zero or zero lateral strains. It has been found that the relationship between the logarithm of the relative compression after complete or incomplete liquefaction and the logarithm of the maximum shear strain induced during preceding undrained cyclic loading is approximately linear over a range of maximum shear strain from 0.01% to 10% and of relative densities from 20% to 90% for five Sands under non-zero or zero lateral strain conditions. The results predicted by the proposed method compare favorably with experimental observations of shaking table tests on Saturated Sand in a laminar container. The proposed method may therefore be used as a first approximation for estimating earthquake-induced settlements of Saturated Sand deposits.
