Strain softening of K0-consolidated Changi sand under plane-strain conditions

Wanatowski, Dariusz; Chu, Jian

doi:10.1007/s11440-006-0004-x

Cited by 5 publications

(9 citation statements)

References 33 publications

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“…The typical mode of the shear bands developed during strain path tests is identical with that observed under drained and undrained conditions [37]. An example of the shear band observed at the end of Test SP26 (p 0 c ¼ 404 kPa, e c = 0.731, de v /de 1 = -0.4) is shown in Fig.…”

Section: Shear Band Formationsupporting

confidence: 72%

“…Therefore, for a given de v /de 1 there is a critical void ratio, at which the strain softening can be initiated. For example, when de v /de 1 = 0 there is a critical point C 0 , at which e cs = 0.884 [37]. Similarly, for a given void ratio, there is a critical value of de v /de 1 , at which strain softening can be initiated.…”

Section: Discussionmentioning

confidence: 99%

“…The average values of 55.6°and 56.2°were obtained for medium loose and medium dense sand, respectively. It has been observed that shear band inclinations were best predicted by the Roscoe solution [37]. …”

Section: Shear Band Formationmentioning

confidence: 99%

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Strain-softening behaviour of sand in strain path testing under plane-strain conditions

Wanatowski

Chu

2008

Acta Geotech.

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Experimental data are presented in this paper to study the strain-softening behaviour of sand under planestrain conditions. K 0 consolidated strain path tests were conducted using a new plane-strain apparatus. The stressstrain behaviour of medium dense sand under plane-strain conditions was characterized. The test results show that the occurrence of pre-failure strain softening under planestrain conditions is affected by the void ratio, the strain increment ratio and the initial effective confining stress. This is consistent with previous findings established under axisymmetric conditions. However, a pre-failure strainsoftening behaviour in plane-strain tests conducted under high-confining stresses may consist of three stages, namely, material softening, banding softening, and ultimate state. This observation is different from that in triaxial tests where banding softening does not normally occur. List of symbols b(r 2 -r 3 )/(r 1 -r 3 ) de 1 axial strain increment de v volumetric strain increment de v /de 1 strain increment ratio e void ratio I 1 first principal stress invariant I 1 = r 1 + r 2 + r 3 I 3 third principal stress invariant I 3 = r 1 r 2 r 3 m constant in Lade's failure criterion in Eq. (5) p 0 mean effective stress p 0 ¼ 1 3 (r 0 1 þ r 0 2 þ r 0 3 Þ p a atmospheric pressure q deviatoric stress q ¼ 1 ffiffi ffi 2 p (r 1 ½ Àr 2 ) 2 þ (r 2 À r 3 ) 2 þ(r 3 À r 1 ) 2 1 2 Du excess pore water pressure b parameter in Eq.axial strain e s deviatoric strain, e s ¼ ffiffi 2 p 3 e 1 À e 2 ð Þ 2 þ e 2 À e 3 ð Þ 2 h þ e 3 À e 1 ð Þ 2 1 2 e v volumetric strain, e v ¼ e 1 þ e 2 þ e 3 / 0 effective friction angle of soil g effective stress ratio, g = q/p 0 g 1 symbol of Lade's failure criterion in Eqs. (4) and (5) g 1max constant in Lade's failure criterion in Eq. (4) M effective stress ratio g at critical state l Lode stress parameter, l ¼ 2r 0 2 À r 0 3 À r 0Lode strain parameter, m ¼ 2de 2 À de 3 À de 1 de 1 À de 3 r 0 1 major principal effective stress r 0 2 intermediate principal effective stress r 0 3

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Section: Shear Band Formationsupporting

confidence: 72%

Section: Discussionmentioning

confidence: 99%

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Strain-softening behaviour of sand in strain path testing under plane-strain conditions

Wanatowski

Chu

2008

Acta Geotech.

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“…This might be attributed to the fact that strains were measured externally in the experimental tests [50]; therefore, the measured initial stiffness is lower than the value that would have been obtained if local deformation measurement techniques were employed [45,50]. Accordingly, best fit parameters c d and c l ended up with values higher than expected, as required to reproduce a correct elastoplastic stiffness with an unrealistically low estimation for elastic In this section, the predictive capability of the model for nontriaxial conditions is analyzed using results of a series of drained plane strain compression tests of K 0 -consolidated Changi sand performed by Wanatowski and Chu [52]. Table 2 shows the material state of three samples after K 0 consolidation and before drained PSC shearing at constant r 3 .…”

Section: Model Response In Undrained Triaxial Compressionmentioning

confidence: 99%

“…The first two parameters, namely e min = 0.533 and e max = 0.916 were taken from [52]. The stress state after full softening was used to compute / c = 37.5°, because at this state no other parameter has any influence in the results of the simulations.…”

Section: Model Response In Undrained Triaxial Compressionmentioning

confidence: 99%

Formulation and validation of a constitutive model for sands in monotonic shear

Sfriso

Weber

2010

Acta Geotech.

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A constitutive model for sands in monotonic shear is presented. The model is designed to simulate the behavior of sands in the whole stress and strain range of engineering interest with enough accuracy for practical usage. Material parameters were chosen to be state independent and easy to calibrate using conventional testing procedures. The formulation is based on effective stresses, pressure-dependent hyperelasticity, non-associative elastoplasticity, an isotropic hardening law and Rowe's stress-dilatancy theory. The implementation of Rowe's stress-dilatancy theory within the framework of elastoplasticity theory is discussed. It is found that Rowe's theory produces a volumetric plastic strain rate function that has a discontinuity in its first derivative w.r.t. stress, and a smoothed form is proposed instead. Finally, some experimental tests are simulated and the results are briefly discussed.

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