Deformation Behavior of Anisotropic Dense Sand Under Principal Stress Axes Rotation

Miura, Kiyotaka; Miura, Seiichi; Toki, Shosuke

doi:10.3208/sandf1972.26.36

Cited by 284 publications

(239 citation statements)

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“…Arthur et al [4] applied controlled changes of principal stress axes with the Directional Shear Cell and studied sample behaviour to shearing after a pre-loading to a high stress ratio and a rotation of principal stress axes. Extensive experimental observations on sand responses to principal stress rotation have been published since the 1980s' [5][6][7][8][9][10] using the hollow cylindrical device which offers independent control of the magnitudes and directions of principal stresses. Non-coaxial deformation and volume contraction are typical deformation characteristics observed when rotating the principal stress axes [6,7,[11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Macro deformation and micro structure of 3D granular assemblies subjected to rotation of principal stress axes

Yang

2016

Granular Matter

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This paper presents a numerical investigation on the behavior of three dimensional granular materials during continuous rotation of principal stress axes using the discrete element method. A dense specimen has been prepared as a representative element using the deposition method and subjected to stress rotation at different deviatoric stress levels. Significant plastic deformation has been observed despite that the principal stresses are kept constant. This contradicts the classical plasticity theory, but is in agreement with previous laboratory observations on sand and glass beads. Typical deformation characteristics, including volume contraction, deformation non-coaxiality, have been successfully reproduced. After a larger number of rotational cycles, the sample approaches the ultimate state with constant void ratio and follows a periodic strain path. The internal structure anisotropy has been quantified in terms of the contact-based fabric tensor. Rotation of principal stress axes densifies the packing, and leads to the increase in coordination numbers. A cyclic rotation in material anisotropy has been observed. The larger the stress ratio, the structure becomes more anisotropic. A larger fabric trajectory suggests more significant structure re-organization when rotating and explains the occurrence of more significant strain rate. The trajectory of the contactnormal based fabric is not centered in the origin, due to the anisotropy in particle orientation generated during sample generation which is persistent throughout the shearing process. The sample sheared at a lower intermediate principal stress ratio (b = 0.0) has been observed to approach a smaller strain trajectory as compared to the case b = 0.5, consistent with a smaller fabric trajectory and less significant structural re-organisation. It also experiences less volume contraction with the out-of plane strain component being dilative.

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Section: Introductionmentioning

confidence: 99%

Macro deformation and micro structure of 3D granular assemblies subjected to rotation of principal stress axes

Yang

2016

Granular Matter

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“…Extensive efforts of experimental testing and constitutive modelling have been made to better estimate the strength and deformation of anisotropic granular soils [2,3,5,6,9,19,22,27,29,32,34,42]. Experiments have been carried out by preparing and testing specimens of different tilting angles or loading a soil specimen along various directions [20,29,30,45]. In addition, numerical simulations using discrete element methods [8] are reported and found in qualitative agreement with laboratory observations [22,31,41].…”

Section: Introductionmentioning

confidence: 88%

“…The non-coincidence between fabric anisotropy and force anisotropy can potentially further reduce material stress ratio by a factor of κ as evidenced in Eq. (29). Figure 4 plots κ in terms of the anisotropy ratio /B f 1 and the angle ψ − β f 1 /2.…”

Section: Strength Anisotropymentioning

confidence: 99%

“…12, the solid symbols are the data measured on the specimen boundaries, while the hollow symbols are the predictions from Eq. (29).…”

Section: Deformation Non-coaxialitymentioning

confidence: 99%

“…Strength anisotropy is of key engineering importance in estimating the stability of infrastructures and has therefore attracted much research interest. Extensive efforts of experimental testing and constitutive modelling have been made to better estimate the strength and deformation of anisotropic granular soils [2,3,5,6,9,19,22,27,29,32,34,42]. Experiments have been carried out by preparing and testing specimens of different tilting angles or loading a soil specimen along various directions [20,29,30,45].…”

Section: Introductionmentioning

confidence: 99%

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Fabric, force and strength anisotropies in granular materials: a micromechanical insight

2014

Acta Mech

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In micromechanics, the stress-force-fabric (SFF) relationship is referred to as an analytical expression linking the stress state of a granular material with microparameters on contact forces and material fabric. This paper employs the SFF relationship and discrete element modelling to investigate the micromechanics of fabric, force and strength anisotropies in two-dimensional granular materials. The development of the SFF relationship is briefly summarized while more attention is placed on the strength anisotropy and deformation non-coaxiality. Due to the presence of initial anisotropy, a granular material demonstrates a different behaviour when the loading direction relative to the direction of the material fabric varies. Specimens may go through various paths to reach the same critical state at which the fabric and force anisotropies are coaxial with the loading direction. The critical state of anisotropic granular material has been found to be independent of the initial fabric. The fabric anisotropy and the force anisotropy approach their critical magnitudes at the critical state. The particle-scale data obtained from discrete element simulations of anisotropic materials show that in monotonic loading, the principal force direction quickly becomes coaxial with the loading direction (i.e. the strain increment direction as applied). However, material fabric directions differ from the loading direction and they only tend to be coaxial at a very large shear strain. The degree of force anisotropy is in general larger than that of fabric anisotropy. In comparison with the limited variation in the degree of force anisotropy with varying loading directions, the fabric anisotropy adapts in a much slower pace and demonstrates wider disparity in the evolution in the magnitude of fabric anisotropy. The difference in the fabric anisotropy evolution has a more significant contribution to strength anisotropy than that of force anisotropy. There are two key parameters that control the degree of deformation non-coaxiality in granular materials subjected to monotonic shearing: the ratio between the degrees of fabric anisotropy and that of force anisotropy and the angle between the principal fabric direction and the applied loading direction.

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Stabilities and Isomeric Equilibria in Aqueous Solution of Monomeric Metal Ion Complexes of Adenosine 5′‐Diphosphate (ADP³⁻) in Comparison with Those of Adenosine 5′‐Monophosphate (AMP²⁻)

Bianchi

Sajadi

Song

et al. 2003

Chemistry A European J

124

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Under experimental conditions in which the self-association of the adenine phosphates (AP), that is, of adenosine 5'-monophosphate (AMP(2-)) and adenosine 5'-diphosphate (ADP(3-)), is negligible, potentiometric pH titrations were carried out to determine the stabilities of the M(H;AP) and M(AP) complexes where M(2+)=Mg(2+), Ca(2+), Sr(2+), Ba(2+), Mn(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), or Cd(2+) (25 degrees C; I=0.1 M, NaNO(3)). It is concluded that in the M(H;AMP)(+) species M(2+) is bound at the adenine moiety and in the M(H;ADP) complexes at the diphosphate unit; however, the proton resides in both types of monoprotonated complexes at the phosphate residue. The stabilities of nearly all the M(AMP) and M(ADP)(-) complexes are significantly larger than what is expected for a sole coordination of M(2+) to the phosphate residue. This increased complex stability is attributed, in agreement with previous (1)H NMR shift studies and further information existing in the literature, to the formation of macrochelates of the phosphate-coordinated metal ions with N7 of the adenine residues. On the basis of recent measurements with simple phosphate monoesters and phosphonate ligands (R-MP(2-)) as well as with diphosphate monoesters (R-DP(3-)), where R is a noncoordinating and noninhibiting residue, the increased stabilities of the M(AMP) and M(ADP)(-) complexes due to the M(2+)-N7 interaction could be evaluated and the extent of macrochelate formation calculated. The results show that the formation degrees of the macrochelates for the complexes of the alkaline earth ions are small (about 15 % at the most), whereas for the 3d metal ions as well as for Zn(2+) and Cd(2+) the formation degrees vary between about 15 % (Mn(2+)) and 75 % (Ni(2+)) with values of about 40 and 50 % for Zn(2+) and Cu(2+), respectively. It is interesting to note, taking earlier results for M(ATP)(2-) complexes also into account (ATP(4-)=adenosine 5'-triphosphate), that for a given metal ion in nearly all instances the formation degrees of the macrochelates are within the error limits the same for M(AMP), M(ADP)(-) and M(ATP)(2-) complexes; except for Co(2+) and Ni(2+) it holds M(AMP) > M(ADP)(-) approximately M(ATP)(2-). This result is astonishing if one considers that the absolute stability constants of these complexes, which are determined largely by the affinity of the phosphate residues, can differ by more than two orders of magnitude. The impact and conclusions of these observations for biological systems are shortly lined out.

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Deformation Behavior of Anisotropic Dense Sand Under Principal Stress Axes Rotation

Cited by 284 publications

References 10 publications

Macro deformation and micro structure of 3D granular assemblies subjected to rotation of principal stress axes

Macro deformation and micro structure of 3D granular assemblies subjected to rotation of principal stress axes

Fabric, force and strength anisotropies in granular materials: a micromechanical insight

Stabilities and Isomeric Equilibria in Aqueous Solution of Monomeric Metal Ion Complexes of Adenosine 5′‐Diphosphate (ADP³⁻) in Comparison with Those of Adenosine 5′‐Monophosphate (AMP²⁻)

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Deformation Behavior of Anisotropic Dense Sand Under Principal Stress Axes Rotation

Cited by 284 publications

References 10 publications

Macro deformation and micro structure of 3D granular assemblies subjected to rotation of principal stress axes

Macro deformation and micro structure of 3D granular assemblies subjected to rotation of principal stress axes

Fabric, force and strength anisotropies in granular materials: a micromechanical insight

Stabilities and Isomeric Equilibria in Aqueous Solution of Monomeric Metal Ion Complexes of Adenosine 5′‐Diphosphate (ADP3−) in Comparison with Those of Adenosine 5′‐Monophosphate (AMP2−)

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Resources

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Stabilities and Isomeric Equilibria in Aqueous Solution of Monomeric Metal Ion Complexes of Adenosine 5′‐Diphosphate (ADP³⁻) in Comparison with Those of Adenosine 5′‐Monophosphate (AMP²⁻)