Similarity of internal stability criteria for granular soils

1992 ◽  
Vol 29 (4) ◽  
pp. 711-713 ◽  
Author(s):  
Robert P. Chapuis
Keyword(s):  
Grain Size ◽  
Groundwater Flow ◽  
Distribution Curve ◽  
Fine Particles ◽  
Frost Damage ◽  
Granular Soils ◽  
Internal Stability ◽  
Stability Criteria ◽  
Mathematical Expressions ◽  
Internal Instability

Internal instability produces segregation in fine particles, modifies drainage properties, and increases pore pressures, capillary retention, and possible frost damage. Three criteria are commonly used to assess the internal instability of granular soils. It is shown here that they can take similar mathematical expressions where the secant slope of the grain-size distribution curve indicates the risk of internal instability. Key words : suffossion, groundwater flow, gradation.

Comparison of two criteria for internal stability of granular soil

2008 ◽  
Vol 45 (9) ◽  
pp. 1303-1309 ◽  
Author(s):  
Maoxin Li ◽  
R. Jonathan Fannin
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Distribution Curve ◽  
Seepage Flow ◽  
Granular Soil ◽  
Engineering Practice ◽  
Internal Stability ◽  
Subtle Difference ◽  
Internal Instability ◽  
The Difference

Internal instability describes the loss of soil particles as a result of seepage. Two criteria are commonly used to determine the potential for such instability within a granular soil that is subject to seepage flow. The criteria are similar, in that they both require an evaluation of the slope of the grain-size distribution curve. However, the manner in which the evaluation is made yields a subtle difference between the respective methods. Comparison of the methods reveals that the difference can have implications for evaluation of broadly graded soils, and guidance is suggested for their use with greater confidence in engineering practice.

Internal stability of granular filters

1985 ◽  
Vol 22 (2) ◽  
pp. 215-225 ◽  
Author(s):  
T. C. Kenney ◽  
D. Lau
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Particle Size Distribution ◽  
Granular Material ◽  
Key Words ◽  
Distribution Curve ◽  
Internal Stability ◽  
Small Particles ◽  
Particle Size Distribution Curve ◽  
Internal Instability

Internal stability of a granular material results from its ability to prevent loss of its own small particles due to disturbing forces such as seepage and vibration. Internal instability results from the inability of a soil to act as a filter to prevent loss of its own small particles.Within pores in the load-bearing fabric of a cohesionless, granular material there can exist loose particles, and whether or not these particles can be removed by seepage depends on (i) particle size distribution curve of the whole material, (ii) density of the compacted material, and (iii) severity of the disturbing forces.Results of seepage tests are presented for a variety of compacted, cohesionless materials, some of which experienced loss of small particles (unstable gradings) and others of which experienced no such loss (stable gradings). From a synthesis of these results a method is proposed for evaluating the potential for grading instability based on the shape of a material's grain size curve. However, the surest method of making such an evaluation is to perform seepage tests following the procedure described in the paper. Key words: internal stability, grading stability, suffosion, tests, filters.

A new theoretical method to evaluate the internal stability of granular soils

2012 ◽  
Vol 49 (1) ◽  
pp. 45-58 ◽  
Author(s):  
Nicola Moraci ◽  
Maria Clorinda Mandaglio ◽  
Domenico Ielo
Keyword(s):  
Fine Particles ◽  
Filter Design ◽  
Critical Diameter ◽  
Theoretical Method ◽  
Rigid Wall ◽  
Spherical Particles ◽  
Granular Soils ◽  
Internal Stability ◽  
Granular Base ◽  
Geotextile Filter

The geotextile filter design is particularly complex when granular base soils are internally unstable. In these conditions, the design criteria available in literature are not always reliable. This paper deals with a new theoretical method developed to evaluate the internal stability of granular soils. To simulate, theoretically, the filtration process inside these soils, a set of spherical particles and different soil relative densities have been considered. The soil has been represented by means of a sequence of parallel layers, containing constrictions and particles, placed upon each other at a distance, in the direction of hydraulic flow, which is a function of the soil relative density. The movement of the fine particles through the different soil layers has been simulated by means of a mechanism that compares each particle contained in the i layer with the constrictions contained in the next i + 1 layer. The results of the numerical simulations were used to evaluate the internal stability of the analyzed granular soil and the corresponding critical diameter of suffusion, Dc. Finally, the reliability of the proposed theoretical method was evaluated by means of the results of experimental long-term filtration tests performed using a rigid-wall permeameter on different unstable granular soils.

scholarly journals Flow Characteristics and Grain Size Distribution of Granular Gangue Mineral by Compaction Treatment

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Ran Yuan ◽  
Dan Ma ◽  
Hongwei Zhang
Keyword(s):  
Weight Loss ◽  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Water Flow ◽  
Fine Particles ◽  
Flow Characteristics ◽  
Test System ◽  
Chemical Components ◽  
Gangue Mineral

A test system for water flow in granular gangue mineral was designed to study the flow characteristics by compaction treatment. With the increase of the compaction displacement, the porosity decreases and void in granular gangue becomes less. The main reason causing initial porosity decrease is that the void of larger size is filled with small particles. Permeability tends to decrease and non-Darcy flow factor increases under the compaction treatment. The change trend of flow characteristics shows twists and turns, which indicate that flow characteristics of granular gangue mineral are related to compaction level, grain size distribution, crushing, and fracture structure. During compaction, larger particles are crushed, which in turn causes the weight of smaller particles to increase, and water flow induces fine particles to migrate (weight loss); meanwhile, a sample with more weight of size (0–2.5 mm) has a higher amount of weight loss. Water seepage will cause the decrease of some chemical components, where SiO2 decreased the highest in these components; the components decreased are more likely locked at fragments rather than the defect of the minerals. The variation of the chemical components has an opposite trend when compared with permeability.

Uniformity of Grain Coarsening in Submicron Grained Al-Sc Alloy Containing Local Variations in Texture

2005 ◽  
Vol 495-497 ◽  
pp. 609-614
Author(s):  
Michael Ferry
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Fine Particles ◽  
Volume Fraction ◽  
Marked Change ◽  
Grain Coarsening ◽  
Large Volume Fraction ◽  
Orientation Gradient ◽  
Distribution Boundary

The effect of fine particles on the uniformity of grain coarsening in a submicron grained Al-Sc alloy containing significant local variations in texture has been investigated using high resolution EBSD. The alloy was processed by severe plastic deformation and low temperature ageing to generate a fine-grained (0.8 µm diameter) microstructure containing either a dispersion of nanosized Al3Sc particles or a particle-free matrix. The initial processing generated a uniform grain size distribution, but the distribution of grain orientations was inhomogeneous with the microstructure containing colonies of grains consisting predominantly of either HAGBs or LAGBs with the latter possessing orientation gradients of up to 10 o/µm. Despite the marked differences in boundary character between these regions, the alloy undergoes slow and uniform grain coarsening during annealing at temperatures up to 500 oC with no marked change in the grain size distribution, boundary distribution and texture. A model of grain coarsening that takes into account the influence of fine particles on the kinetics of grain growth within an orientation gradient is outlined. The model predicts that a large volume fraction of fine particles (large f/r-value) tends to homogenize the overall rate of grain coarsening despite the presence of orientation gradients in the microstructure.

scholarly journals Characterization of sand boils with grading entropy

2012 ◽  
pp. 73-88
Author(s):  
Laslo Nadj
Keyword(s):  
Grain Size ◽  
Distribution Curve ◽  
Practical Consideration ◽  
Implicit Information ◽  
Sand Boil ◽  
Sand Boils ◽  
Grain Distribution ◽  
Soil Behaviour ◽  
The Relationship

Grain size and grain distribution by size are dominant factors determining soil behaviour. The shape and position of a grain distribution curve contain implicit information about the propensity of sand boiling or piping at flood conditions. The author used 1040-grain distribution curves taken from 12 sand boil locations to study the relationship between sand boils, hydraulic soil failures and entropy. The results have justified the hypotheses and indicated some fairly important details for practical consideration. Calculating grain distribution entropy is not ?magic? with mathematics: it simply helps put the expected behaviour of soils into a different perspective and promotes orientation for classifying soils according to a new parameter related to grain movement.

scholarly journals Comparison of Different Empirical Correlations to Estimate Permeability Coefficient of Quaternary Danube Soils

2018 ◽  
Author(s):  
Miklós Pap ◽  
András Mahler
Keyword(s):  
Grain Size ◽  
Permeability Coefficient ◽  
Carpathian Basin ◽  
Laboratory Measurement ◽  
Granular Soils ◽  
Empirical Correlations ◽  
Soil Parameter ◽  
Measurement Results

Permeability coefficient is the most significant soil parameter in seepage calculations. It has been recognized that permeability of granular soils is strongly related to the grain size, thus numerous empirical correlations have been developed to estimate permeability using its grain size characteristics. In this study the empirical correlations proposed by Hazen (1911), Carrier (2003) and Chapuis (2004) are evaluated and compared to laboratory measurement results. Quaternary Danube soils are very typical in the Carpathian basin, thus their permeability is an important question in many geotechnical applications.

scholarly journals Comparison of physical and mechanical properties of mining waste with a grain size up to 2 mm reinforced with cement CEM I and CEM III

2019 ◽  
Vol 106 ◽  
pp. 01023
Author(s):  
Justyna Morman-Wątor
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Fine Particles ◽  
Physical And Mechanical Properties ◽  
Mining Waste ◽  
Soil Testing ◽  
Mechanical Parameters ◽  
Freeze Resistance

The article presents the results of tests for mining waste mixtures - cement. The addition of cement was aimed at limiting the leaching of fine particles and improving physical and mechanical parameters. The studies used cement CEM I 42.5 R and CEM III/ A 42.5N - LH / HSR / NA and plasticizing sealant. The paper presents the results of freeze resistance, swelling tests, pH of water leachate and oedometer soil testing.

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