Determination of the equivalent intergranular void ratio - Application to the instability and the critical state of silty sand

Cohesive and non-cohesive soils show a number of properties typical of a given category. Cohesive soils are characterized by cohesion, and the properties of compacted soils closely depend on moisture at compaction. However, many researchers have found the existence of so-called mixed or transitional soils. Compacted transitional soils, macroscopically recognized as non-cohesive, are characterized by mechanical properties and hydraulic conductivity which are strictly dependent on the moisture content at compaction. The aim of this work is to show the influence of the content of fine particles in fly ash on the variation of California Bearing Ratio (CBR) values as a parameter strictly dependent on initial compaction. The CBR values were interpreted in terms of moisture at compaction, void ratio and intergranular void ratio. Three different research samples were selected with fine contents of 45%, 55% and 70%; all samples corresponded in terms of grading with sandy silt. Fly ash containing only non-plastic fines behaved as cohesive soils despite the lack of plasticity. The CBR values decreased with increasing moisture at compaction or void ratio. The CBR values, plotted as a function of the intergranular void ratio, have lower penetration resistance together with fine content.

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Predicting the engineering and transport properties of soils using fractal equivalent circuit model: Laboratory experiments

Geophysics ◽

10.1190/geo2010-0299.1 ◽

2011 ◽

Vol 76 (5) ◽

pp. F329-F338 ◽

Cited By ~ 7

Author(s):

Fred Kofi Boadu

Keyword(s):

Hydraulic Conductivity ◽

Transport Properties ◽

Equivalent Circuit ◽

Void Ratio ◽

Equivalent Circuit Model ◽

Circuit Model ◽

Dry Density ◽

Electrical Measurements ◽

Intergranular Void Ratio ◽

Intergranular Void

Frequency-dependent electrical measurements of soils contain useful information about their texture and structure that can be linked to their engineering and transport properties. We performed frequency-dependent electrical measurements on 29 natural soils with wide variability in physical and textural properties in a laboratory environment at a constant stress level and in the frequency range of 0.01 Hz–10 kHz. The engineering and hydraulic properties of these soils, that is, the hydraulic conductivity [Formula: see text], void ratio [Formula: see text], fines content [Formula: see text], intergranular void ratio [Formula: see text] and the dry density [Formula: see text] are concurrently measured. The electrical behaviors of the soils are modeled with an equivalent circuit model, which are described by six circuit parameters. Relationships between the circuit parameters and the soil properties (geotechnical engineering and hydraulic) are investigated. Crossplots of frequency exponent [Formula: see text] and resistivity [Formula: see text] and that of [Formula: see text] and grain percent resistivity [Formula: see text] clusters soils with high and low values of hydraulic conductivity, whereas crossplots of relaxation time [Formula: see text] and [Formula: see text] clusters soils with high and low intergranular void ratio. Regression models are developed using the parameters [Formula: see text] and [Formula: see text] to predict the hydraulic conductivity with [Formula: see text]; [Formula: see text] and [Formula: see text] to predict the intergranular void ratio with [Formula: see text] and [Formula: see text] and [Formula: see text] to predict the dry density with [Formula: see text].

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Undrained shear strength of sand-silt mixture: Effect of intergranular void ratio and other parameters

KSCE Journal of Civil Engineering ◽

10.1007/s12205-011-1051-x ◽

2011 ◽

Vol 15 (8) ◽

pp. 1335-1342 ◽

Cited By ~ 7

Author(s):

Mostefa Belkhatir ◽

Hanifi Missoum ◽

Ahmed Arab ◽

Noureddine Della ◽

Tom Schanz

Keyword(s):

Shear Strength ◽

Void Ratio ◽

Undrained Shear Strength ◽

Mixture Effect ◽

Intergranular Void Ratio ◽

Undrained Shear ◽

Intergranular Void

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Definition and experimental determination of a soil-water retention surface

Canadian Geotechnical Journal ◽

10.1139/t09-123 ◽

2010 ◽

Vol 47 (6) ◽

pp. 609-622 ◽

Cited By ~ 61

Author(s):

S. Salager ◽

M. S. El Youssoufi ◽

C. Saix

Keyword(s):

Water Content ◽

Soil Water ◽

Water Retention ◽

Void Ratio ◽

Silty Sand ◽

Soil Water Retention ◽

Initial Void Ratio ◽

Hydromechanical Behaviour ◽

Determination Methods

This paper deals with the definition and determination methods of the soil-water retention surface (SWRS), which is the tool used to present the hydromechanical behaviour of soils to highlight both the effect of suction on the change in water and total volumes and the effect of deformation with respect to the water retention capability. An experimental method is introduced to determine the SWRS and applied to a clayey silty sand. The determination of this surface is based on the measurement of void ratio, suction, and water content along the main drying paths. These paths are established for five different initial states. The experimental results allow us to define the parametric equations of the main drying paths, expressing both water content and void ratio as functions of suction and initial void ratio. A model of the SWRS for clayey silty sand is established in the space (void ratio – suction – water content). This surface covers all possible states of the soil inside the investigated range for the three variables. Finally, the SWRS is used to study the relations between water content and suction at a constant void ratio and between void ratio and suction at a constant water content.

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Mechanical characteristics of undisturbed coral gravel soils: The intergranular void ratio as a common governing parameter

SOILS AND FOUNDATIONS ◽

10.1016/j.sandf.2017.08.007 ◽

2017 ◽

Vol 57 (5) ◽

pp. 760-775 ◽

Cited By ~ 3

Author(s):

Yoichi Watabe ◽

Shinji Sassa ◽

Takashi Kaneko ◽

Yukio Nakata

Keyword(s):

Void Ratio ◽

Mechanical Characteristics ◽

Governing Parameter ◽

Intergranular Void Ratio ◽

Intergranular Void

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Assessing Relations Between Electrical and Geotechnical Properties of Sand-Clay Mixtures Using Jonscher Fractal Power Law Model

Journal of Environmental and Engineering Geophysics ◽

10.2113/jeeg24.1.77 ◽

2019 ◽

Vol 24 (1) ◽

pp. 77-85

Author(s):

Fred Kofi Boadu ◽

Samuel Ampadu

Keyword(s):

Water Content ◽

Effective Stress ◽

Power Law ◽

Void Ratio ◽

Geotechnical Properties ◽

Dry Density ◽

Power Law Model ◽

Stress Levels ◽

Intergranular Void Ratio ◽

Intergranular Void

The geotechnical properties of unconsolidated geo-materials such as soils are influenced by modifications of their micro-structure, texture, mineralogy, water content and imposed effective stress levels. Fundamental relations between the characteristic electrical parameters describing the electrical responses soils based on a fractal power law model with scaling properties, and parameters influencing their geotechnical behavior are investigated. Low frequency electrical conductivity laboratory measurements were performed on sand and clay mixtures subjected to varying effective stress levels with concurrent measurements of their geotechnical properties. The conductivity spectra of the mixtures were described using a Jonscher fractal power law model characterized with three characteristic parameters, the dc conductivity ( σ dc ), the characteristic frequency ( f c ) and an exponent ( n). Changes in effective stress, water content, clay content, and other engineering properties of the mixture such as dry density, porosity, pore size and intergranular void ratio are discussed with respect to changes in the electrical parameters. The dc conductivity and characteristic frequency decrease with an increase in effective stress levels. The exponent, however, has the opposite behavior and increases with an increase in effective stress. As the water content increases, σ dc and f c increase while n decreases for all mixtures. With increasing stress levels, the average pore size of the mixtures decreases which results in a decrease in σ dc and f c but an increase in the values of the exponent. An increase in dry density of the mixtures leads to a decrease in σ dc and f c whilst n increases. Both σ dc and f c increase with increase in the intergranular void ratio of the mixture whilst the exponent values decrease with an increase in the intergranular void ratio. This study serves as a contribution to our quest in utilizing electrical geophysical methods, to assess and monitor non-invasively, the geotechnical properties of the subsurface in a less expensive and faster manner.

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Yield strength ratios, critical strength ratios, and brittleness of sandy soils from laboratory tests

Canadian Geotechnical Journal ◽

10.1139/t10-078 ◽

2011 ◽

Vol 48 (3) ◽

pp. 493-510 ◽

Cited By ~ 20

Author(s):

Abouzar Sadrekarimi ◽

Scott M. Olson

Keyword(s):

Yield Strength ◽

Critical State ◽

Void Ratio ◽

Triaxial Compression ◽

Silty Sand ◽

Strength Ratio ◽

Critical Strength ◽

Initial Void Ratio ◽

Ring Shear ◽

Particle Damage

In this study, we performed 26 undrained triaxial compression and 32 constant-volume ring shear tests on two clean sands and one silty sand. We then used these results to evaluate the critical states, and shear strength ratios mobilized at yield and at critical state. We obtained yield strength ratios that ranged from 0.16 to 0.32 and from 0.20 to 0.35 in triaxial compression and ring shear, respectively. Critical strength ratios mobilized prior to particle damage ranged from 0.01 to 0.26 in triaxial compression and from 0.04 to 0.22 in ring shear. Particle damage and shear displacement increased the slopes of the critical-state lines during ring shear testing, and consequently the critical strength ratios incorporating particle damage decreased from 0.02 to 0.12. In addition, specimen brittleness (before particle damage) increases with initial void ratio and state parameter and is affected by initial fabric and particle shape. However, particle damage and crushing considerably increases sand brittleness, making it essentially independent of initial void ratio. A unique relation is found between sand brittleness and critical strength ratio independent of sand type, mode of shear, fabric, and particle damage, which indicates an upper bound critical strength ratio of about 0.3 for mildly contractive sands.

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