scholarly journals Examining the predictive capabilities of a bounding surface plasticity-based hyperelastic constitutive model for unsaturated granular soils

2021 ◽  
Vol 337 ◽  
pp. 02005
Author(s):  
Mehdi Kadivar ◽  
Kalehiwot Nega Manahiloh ◽  
Victor N. Kaliakin
Keyword(s):  
Water Stress ◽  
Constitutive Model ◽  
Characteristic Curve ◽  
Granular Soils ◽  
Bounding Surface ◽  
Bounding Surface Plasticity ◽  
Mechanical Coupling ◽  
Surface Plasticity ◽  
Wide Range ◽  
Unsaturated Granular Soils

The performance of a recently developed state-dependent constitutive model for unsaturated granular soils is evaluated. The model employs the Bounding Surface plasticity framework and evaluates elastic strains assuming hyperelastic behavior. To realistically simulate the deformation of unsaturated granular soils, the mechanical behavior was modeled without a purely elastic component. The inherent hydro-mechanical coupling was realized by introducing a Bishop-type effective stress, an appropriate work-conjugate variable, and a soil-water characteristic curve function. Relevant details about the model development, parameter estimation, and the assessment of the model’s predictive capabilities are presented. The model performance is evaluated with experimental data obtained for drained and constant-water stress paths. With a given a set of parameter values, the model realistically simulates the main features that characterize the shear and volumetric behavior of unsaturated granular soils over a wide range of matric suction, density, and net confining pressure. This is found to be true for both drained and constant-water stress paths.

Isotropic–kinematic hardening model for coarse granular soils capturing particle breakage and cyclic loading under triaxial stress space

2016 ◽  
Vol 53 (4) ◽  
pp. 646-658 ◽  
Author(s):  
Qingsheng Chen ◽  
Buddhima Indraratna ◽  
John P. Carter ◽  
Sanjay Nimbalkar
Keyword(s):  
Cyclic Loading ◽  
Critical State ◽  
Kinematic Hardening ◽  
Plasticity Theory ◽  
Particle Breakage ◽  
Granular Soils ◽  
Stress Space ◽  
Bounding Surface ◽  
Bounding Surface Plasticity ◽  
Surface Plasticity

In this paper, a simple but comprehensive cyclic stress–strain model that incorporates particle breakage for granular soils including ballast and rockfill has been proposed on the basis of bounding surface plasticity theory within a critical state framework. Particle breakage and its effects are captured by a critical state line that is translated in voids ratio–stress space according to the dissipated energy (plastic work), through a hyperbolic function. A comprehensive equation related to particle breakage is proposed for the stress–dilatancy relationship to capture the complex dilatancy of granular soils. By extending Masing’s rule to bounding surface plasticity theory and introducing a generalized homological centre, a combined isotropic–kinematic hardening rule and a mapping rule have been established to simulate more realistically the response of gravelly soils under cyclic loading. The applicability and accuracy of this model are demonstrated by comparing its predictions with experimental results for different types of granular soils, including rockfill, under both monotonic and cyclic loading conditions. This study shows that the model can capture the characteristic features of coarse granular soils under complex loading paths.

A bounding surface plasticity model for sands exhibiting particle crushing

2004 ◽  
Vol 41 (6) ◽  
pp. 1179-1192 ◽  
Author(s):  
Adrian R Russell ◽  
Nasser Khalili
Keyword(s):  
Critical State ◽  
Triaxial Tests ◽  
Compression Tests ◽  
Particle Crushing ◽  
Bounding Surface ◽  
Bounding Surface Plasticity ◽  
Isotropic Compression ◽  
Surface Plasticity ◽  
Wide Range ◽  
Bounding Surfaces

A new bounding surface constitutive model for sands is presented and is suited to a wide range of stresses, including those sufficient to cause particle crushing. The basic concepts of critical state soil mechanics are shown to be valid, and a uniquely shaped critical state line is defined to capture the three modes of plastic deformation observed across a wide range of stresses, including particle rearrangement, particle crushing, and pseudoelastic deformation. A limiting isotropic compression line is separated from the critical state line in the υ – In p′ plane by a constant shift along an elastic unload–reload line. In the deviator stress – mean effective stress (q–p′) plane, the loading and bounding surfaces are homologous about the origin and defined by a simple and versatile function. Isotropic hardening and softening of the loading and bounding surfaces are controlled by plastic volumetric strains. A commonly used non associative flow rule is adopted. Experimental results of monotonically loaded drained and undrained triaxial tests, isotropic compression tests, and oedometric compression tests are presented for a quartz sand and used to calibrate the model. Membrane penetration is accounted for in the model simulations of the test results. A single set of material parameters is introduced enabling rigorous and accurate predictions of stress–strain behaviour in sands.Key words: sand, bounding surface, plasticity, particle crushing.

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