Statically and Dynamically Measured Poisson's Ratio of Granular Soils on Triaxial Laboratory Specimens

Suwal, Laxmi Prasad; Kuwano, Reiko

doi:10.1520/gtj20120108

Cited by 31 publications

(13 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar experimental results were reported by Sharifipour & Dano (2006) where smooth and rough (corroded) ballotini were compared. It is worth mentioning that Suwal & Kuwano (2013) compared the Poisson ratio obtained in static and dynamic tests and found that the dynamic tests gave a larger value.…”

Section: Discussion and Comparison Between Analysis And Experimentsmentioning

confidence: 99%

Quantitative assessment of the influence of surface roughness on soil stiffness

et al. 2015

View full text Add to dashboard Cite

The nature of soil stiffness at small strains remains poorly understood. The relationship between soil stiffness (e.g. shear stiffness, G 0 ) and isotropic confining pressure ( p′) can be described using a power function with exponent (b), that is,, where A is a constant and p r is an arbitrary reference pressure. Experimentally determined values of b are usually around 0·5 and these are higher than the value of 0·33 that can be analytically determined using Hertzian theory. Hertzian theory considers contact between two smooth, elastic spheres; however, in reality, inter-particle contacts in soil are complex with particle shape and surface roughness affecting the interaction. Thus Hertzian theory is not directly applicable to predict real soil stiffness. It has, however, provided a useful basis to develop an analytical framework to consider the influence of particle surface roughness on small-strain soil stiffness. Here, earlier contributions using this framework are extended and improved by paying particular attention to roughness and the tangential contact stiffness. Stiffness values calculated using the newly derived analytical expressions were compared with the results of bender element tests on samples of borosilicate glass beads (ballotini) whose surface roughness was quantified using an optical interferometer. The analytical expression captures the experimentally observed sensitivity of the smallstrain shear modulus to surface roughness.

show abstract

Section: Discussion and Comparison Between Analysis And Experimentsmentioning

confidence: 99%

Quantitative assessment of the influence of surface roughness on soil stiffness

et al. 2015

View full text Add to dashboard Cite

show abstract

“…The discrepancy between statically and dynamically measured small-strain stiffnesses is often noted in experimental research. Generally, G0 dyn gives a greater value than G0 sta [1] since G0 decreases with increasing the strain level, and the dynamic approach gives the stiffness at smaller strains [2]. Discrete Element Method (DEM) simulations provide supplementary particle-scale insights into the overall stiffness and enable precise measurements of the static/dynamic stiffness [3].…”

Section: Introductionmentioning

confidence: 99%

Particle-scale insight into transitional behaviour of gap-graded materials – small-strain stiffness and frequency response

et al. 2019

Self Cite

View full text Add to dashboard Cite

This study aims to develop a fundamental understanding of the role of fine particles on the small-strain stiffness of gap-graded granular soils. Stiffness was measured using cyclic triaxial probes, which give a measure of static stiffness, and dynamic wave propagation data, from which the dynamic stiffness can be measured. Assemblies of loosely packed spherical particles were considered. In the laboratory, local deformation transducers were used to measure the static stiffness, while the dynamic stiffness was calculated from stress wave velocities, measured using planar piezoelectric elements. To relate the particle-scale responses to the overall soil stiffness, complementary discrete element method (DEM) simulations were performed in which both static and dynamic stiffnesses were measured. Both the laboratory and the DEM data indicate that at low fines contents (< 30%) the stiffness decreases with increasing fines content. When the fines content increases from 30% to 35% there is a sharp increase in stiffness with increasing fines content; this is understood to mark the transition point at which the fines start to contribute significantly to the overall behaviour. Analyses of the frequency domain response of shear wave signals revealed that the lowpass frequency increases significantly at this transition point. This observation can be used to develop experimental interpretation protocols to assess to what extent fines are contributing to the overall soil stiffness.

show abstract

“…Consideration of a circular shear plate is relevant as disk-shaped shear plates can be used, e.g. Suwal and Kuwano (2013). The area ratio was varied systematically from 2% to 100% where AT = AR, totalling 12 cases, where time and frequency domain responses of three distinct cases (2%, 20% and 100%) were presented in Fig.…”

Section: S Configurationmentioning

confidence: 99%

“…Consequently dynamic test approaches that measure the velocity of propagation of compression (P-) and shear (S-) waves continue to be developed. These include the torsional resonant column technique (Hardin and Richart 1963), bender and extender elements (Shirley and Hampton 1978;Lings and Greening 2001), and planar piezoelectric elements (Brignoli et al 1996;Ismail and Rammah 2005;Suwal and Kuwano 2013).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Selecting an Appropriate Shear Plate Configuration to Measure Elastic Wave Velocities

Otsubo

O’Sullivan

Ackerley

et al. 2020

Geotechnical Testing Journal

View full text Add to dashboard Cite

The (small-strain) elastic moduli of soil can be determined from stress wave velocity measurements. Bender/extender elements are widely used in laboratory experiments; however, discussion on how to accurately determine wave velocities using this method continues. Planar piezoelectric transducers (sometimes called shear plates) are a relatively new technology, whose use is not yet widely established, that appears to offer some advantages in comparison with bender/extender elements for laboratory geophysics tests. This contribution critically assesses the use of planar piezoelectric elements experimentally and using discrete element method (DEM) simulations. Planar piezoelectric elements capable of generating and receiving either shear or compression waves were placed in the top and base caps of a triaxial apparatus. Samples of glass ballotini were used so that stress wave propagation simulations could be performed on equivalent virtual samples using DEM. The appropriate shear plate configuration to effectively measure the shear wave velocity is explored. Considering both time and frequency domain responses, it is revealed that shear plate signals are sensitive to the surface area and thickness of the piezoelectric elements and to the lateral boundary conditions. Using a shear plate with the widest possible surface area exposed to the soil specimen is recommended to increase the signal-to-noise ratio and to produce more planar shear waves, resulting in a more accurate measurement of shear wave velocity.

show abstract

Statically and Dynamically Measured Poisson's Ratio of Granular Soils on Triaxial Laboratory Specimens

Cited by 31 publications

References 14 publications

Quantitative assessment of the influence of surface roughness on soil stiffness

Quantitative assessment of the influence of surface roughness on soil stiffness

Particle-scale insight into transitional behaviour of gap-graded materials – small-strain stiffness and frequency response

Selecting an Appropriate Shear Plate Configuration to Measure Elastic Wave Velocities

Contact Info

Product

Resources

About