Friction in granular media

Santamarina, Juan Carlos; Shin, Hyunho

doi:10.1201/b10826-20

Cited by 12 publications

(4 citation statements)

References 120 publications

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“…Previous studies by Santamarina and Fam [47], and also Jang and Santamarina [48] indicated the influence of fine particles especially those with significant volume change on shear strength characteristics. Other researchers [49][50][51][52] also indicated that particle shape has an effect on the characteristics of shear strength. This study is limited to soils with negligible volume change.…”

Section: Discussionmentioning

confidence: 95%

Role of Bimodal Water Retention Curve on the Unsaturated Shear Strength

et al. 2022

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Changes in climatic conditions are expected globally resulting in a higher rainfall intensity and longer duration of rainfall. The increase in the rainwater infiltration into the soil contributes to many geotechnical issues, such as excessive settlement, retaining wall failure and rainfall-induced slope failures. These geotechnical problems could be mitigated by the improvement of the problematic soil with the incorporation of the unsaturated soil mechanic principles. Dual-porosity soils or soils with bimodal water retention curve (WRC) are able to retain more water during prolonged drying and they would be able to drain out water faster during intense rainfall to maintain the slope stability. The objective of this study is to investigate the characteristics of the unsaturated shear strength of soil with bimodal WRC. In addition, the new mathematical equation is proposed to estimate the unsaturated shear strength of soils with a bimodal WRC. The results of the study indicated that the nonlinearity of the unsaturated shear strength is a function of the shape of bimodal WRC limited by the first and second air-entry value (AEV) of dual-porosity soils. The proposed equation agreed well with the experimental data of the unsaturated shear strength for dual-porosity soil.

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Section: Discussionmentioning

confidence: 95%

Role of Bimodal Water Retention Curve on the Unsaturated Shear Strength

et al. 2022

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“…The threshold strain estimated using Eq. (3) is γ th j loss ≈ 5 × 10 −4 at p 0 o ¼ 250 kPa (Table 1; see data in Silver and Seed 1971;Dobry et al 1982;Vucetic 1994;Santamarina and Shin 2009).…”

Section: Particle-scale Deformation Mechanisms: Threshold Strainmentioning

confidence: 96%

Soil Response to Repetitive Changes in Pore-Water Pressure under Deviatoric Loading

Park

Santamarina

2020

J. Geotech. Geoenviron. Eng.

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Soils often experience repetitive changes in pore water pressure. This study explores the volumetric and shear response of contractive and dilative sand specimens subjected to repetitive changes in pore water pressure, under constant deviatoric stress in a triaxial cell. The evolution towards a terminal void ratio e T characterizes the volumetric response. The terminal void ratio e T for pressure cycles falls below the critical state line, between e min < e T < e cs. Very dense specimens only dilate if they reach high stress obliquity η max during pressurization. The terminal void ratios for very dense and medium dense specimens do not converge to a single trend. The shear deformation may stabilize at shakedown, or continue in ratcheting mode. The maximum stress obliquity η max is the best predictor of the asymptotic state; shakedown prevails in all specimens subjected to stress obliquity η max < 0.95 • η cs and ratcheting takes place when the maximum stress obliquity approaches or exceeds η max ≥ 0.95 • η cs. Volumetric and shear strains can accumulate when the strain level during pressure cycles exceeds the volumetric threshold strain (about 5 × 10 −4 in this study). A particle-level analysis of contact loss and published experimental data show that the threshold strain increases with confinement p 0 o .

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“…A particularity of numerical granular media is that the macro-properties of a particle assembly differ from the defined micro-properties of individual particles [14]. For example, the particle's friction coefficient micro-property influences the particle rolling behavior and therefore the shear strength of the bulk material [15]. Another important property is the influence of particle shape and roughness (e.g., [7,[16][17][18][19][20]).…”

Section: Introductionmentioning

confidence: 99%

Numerical Characterization of Cohesive and Non-Cohesive ‘Sediments’ under Different Consolidation States Using 3D DEM Triaxial Experiments

et al. 2020

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The Discrete Element Method has been widely used to simulate geo-materials due to time and scale limitations met in the field and laboratories. While cohesionless geo-materials were the focus of many previous studies, the deformation of cohesive geo-materials in 3D remained poorly characterized. Here, we aimed to generate a range of numerical ‘sediments’, assess their mechanical response to stress and compare their response with laboratory tests, focusing on differences between the micro- and macro-material properties. We simulated two endmembers—clay (cohesive) and sand (cohesionless). The materials were tested in a 3D triaxial numerical setup, under different simulated burial stresses and consolidation states. Variations in particle contact or individual bond strengths generate first order influence on the stress–strain response, i.e., a different deformation style of the numerical sand or clay. Increased burial depth generates a second order influence, elevating peak shear strength. Loose and dense consolidation states generate a third order influence of the endmember level. The results replicate a range of sediment compositions, empirical behaviors and conditions. We propose a procedure to characterize sediments numerically. The numerical ‘sediments’ can be applied to simulate processes in sediments exhibiting variations in strength due to post-seismic consolidation, bioturbation or variations in sedimentation rates.

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Friction in granular media

Cited by 12 publications

References 120 publications

Role of Bimodal Water Retention Curve on the Unsaturated Shear Strength

Role of Bimodal Water Retention Curve on the Unsaturated Shear Strength

Soil Response to Repetitive Changes in Pore-Water Pressure under Deviatoric Loading

Numerical Characterization of Cohesive and Non-Cohesive ‘Sediments’ under Different Consolidation States Using 3D DEM Triaxial Experiments

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