Time dependent mechanical behaviour of loose sands

Prisco, Claudio di; Imposimato, S.

doi:10.1002/(sici)1099-1484(199601)1:1<45::aid-cfm3>3.0.co;2-o

Cited by 75 publications

(56 citation statements)

References 12 publications

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“…These suggest that a continuous relative rearrangement of the individual particles occurs towards a more stable structure configuration (Delage et al 1990, Schmertmann, 1991, Di Prisco and Imposimato, 1996, Bowman and Soga, 2003, Miksic and Alava, 2013. The particle rearrangement mechanism, although of unknown origin, should be bounded by the accessible geometrical constraints of the system and thus is relatively limited -as also observed in experiments.…”

Section: Introductionmentioning

confidence: 84%

“…One approach, offered by Di Prisco and Imposimato (1996), Imposimato et al (2000), refers to and is based on the theory of viscoplasticity formulated by Perzyna (1966). Alternatively, Di , Tatsuoka et al (1999), Di Benedetto et al (2001), (2002) proposed a viscous evanescent relationship within a general three-component model framework, recently implemented in finite element method code (Peng et al, 2010).…”

Section: Introductionmentioning

confidence: 94%

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Elasto-plastic model for sand including time effect

Cazacliu¹,

Ibraim

2016

Géotechnique Letters

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Abstract. Time effects on granular soils have been observed in laboratory and in situ tests but cannot be reproduced by classical elasto-plastic models. To address these concerns, existing specific modelling approaches were based on the theory of viscoplasticity formulated by Perzyna or on a viscous evanescent relationship. The present work explores an alternative following an elasto-plastic modelling framework formulated in a multi-axial structure space. The proposed elasto-plastic model is associated with a thixotropic-type framework through the use of a structure parameter, the evolution of which illustrates the competition between two effects: the time-dependent tendency of the granular system to reach its stable configurationrestructuration -and its destructuration under external perturbations. The structure parameter is linked to the existence of a stress dependent target structure towards which the current granular material structure evolves. The time scale is explicitly introduced by postulating a rate for this structure evolution. The modelling of the material behaviour has shown good similarities with the response of granular soils observed in monotonic loading, as well as during creep and variable strain rate loading experiments.

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Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 94%

Elasto-plastic model for sand including time effect

Cazacliu¹,

Ibraim

2016

Géotechnique Letters

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“…The experimental investigation of rate effects in geomaterials has led to regard elastoviscoplasticity as a suitable framework for conceiving constitutive relationships [16][17][18][19][20] and reproducing certain material instabilities [21][22][23]. In addition to experimental motivations, viscoplasticity has also gained further popularity as a simple regularization technique in finite element computations, because it mitigates the mesh-dependence effects arising from bifurcated responses (e.g., strain localization) [15,[24][25][26].…”

Section: F Pisanò and C Di Priscomentioning

confidence: 99%

“…In most cases, the viscous nucleusˆis a non-negative non-decreasing function of the yield function f (ˆ 0 and dˆ=df 0) [19]. Provided the analytical definitions of the yield locus, the plastic potential and the hardening rules, a constitutive model can be easily formulated as either elasto-plastic or elasto-viscoplastic depending on the flow rule adopted.…”

Section: General Conceptsmentioning

confidence: 99%

A stability criterion for elasto‐viscoplastic constitutive relationships

Pisanò

Prisco

2015

Num Anal Meth Geomechanics

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SUMMARYIn this paper, the onset of mechanical instability in time-sensitive elasto-viscoplastic solids is theoretically analyzed at the constitutive level and associated with the occurrence of 'spontaneous accelerations' under stationary external perturbations. For this purpose, a second-order form of Perzyna's constitutive equations is first derived by time differentiation, and a sufficient stability condition is identified for general mixed loading programs. These loading conditions are in fact the most general in both laboratory tests and real boundary value problems, where a combination of certain stress and strain components is known/prescribed.The theoretical analysis leads to find precise stability limits in terms of material hardening modulus. In the case of constitutive relationships with isotropic strain-hardening, no instabilities are possible while the hardening modulus is larger than the so-called 'controllability modulus' defined for (inviscid) elasto-plastic materials. It is also shown that the current stress/strain rate may also directly influence the occurrence of elasto-viscoplastic instability, which is at variance with elasto-plastic inviscid media.

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“…Past researchers have studied the pre-failure instability of sands (see, e.g., [22][23][24][25][26][27][28]). The works of Lade and Yamamuro [29,30], Zlatovic and Ishihara [31], Chu et al [32] and Wood et al [33], among others, point out the role played by the grain size distribution on the occurrence of instability.…”

Section: Failure Initiationmentioning

confidence: 99%

A laboratory investigation on an undisturbed silty sand from a slope prone to landsliding

2010

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A laboratory investigation is presented for undisturbed samples of a silty sand under saturated conditions. The soil was sampled from test pits south of Rüdlingen in North-East Switzerland, where a landslide triggering experiment was carried out on a steep forest slope. The aim of the work was to characterise the behaviour of the soil in triaxial tests, in the light of the possible failure mechanisms of the slope. Conventional drained and undrained triaxial tests were conducted to detect critical state conditions as well as peak shear strength as a function of confining pressure. Soil specimens were also exposed to stress paths simulating in situ water pressure increase to study the stress-strain response and to enhance the ability to predict failure conditions more accurately in the future. Possible unstable response along the stress paths analysed was investigated by means of second order work and strain acceleration. The results show that temporary unstable conditions may be encountered for this soil at stress ratios below ultimate failure and even below critical state line, depending on void ratio, drainage conditions and time dependent compressibility. A modified state parameter is explored as a potentially useful tool to discriminate conditions leading to eventual collapse.

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Time dependent mechanical behaviour of loose sands

Cited by 75 publications

References 12 publications

Elasto-plastic model for sand including time effect

Elasto-plastic model for sand including time effect

A stability criterion for elasto‐viscoplastic constitutive relationships

A laboratory investigation on an undisturbed silty sand from a slope prone to landsliding

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