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Journal ArticleDOI: 10.1080/17486025.2019.1648881

Assessment of the correlation between grain angularity parameter and friction index of sand containing low plastic fines

04 Mar 2021-Geomechanics and Geoengineering (Informa UK Limited)-Vol. 16, Iss: 2, pp 133-149
Abstract: This paper describes a fundamental research to explore the impact of grain angularity on theinstability and steady state friction angles of binary mixtures through laboratory triaxial compression t...

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7 results found


Open accessJournal Article
Abstract: Soils that exhibit nonassociated flow may, according to stability postulates by Drucker and by Hill, become unstable when exposed to certain stress paths inside the failure surface. Series of conventional triaxial tests on fully saturated and on partly saturated specimens were performed under drained and undrained conditions to study the regions of stable and unstable behavior. For specimens that compress and have degrees of saturation higher than critical, undrained conditions lead to effective stress paths directed within the region of potential instability, and instability was observed provided the yield surface opens up in the outward direction of the hydrostatic axis. Thus, instability occurs inside the failure surface. Instability is not synonymous with failure, although both may lead to catastrophic events. The location of the instability line is discussed. Examples of a shallow submarine slope and a nearly fully saturated steeper slope representing a tailings dam, which both should remain stable a...

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Topics: Liquefaction (58%)

286 Citations


Journal ArticleDOI: 10.1007/S40515-020-00135-6
01 Jun 2021-
Abstract: This paper presents the results of an experimental investigation carried out to evaluate the effects of fly ash (FA) on the coarse-grained soils compaction response and shear characteristics for the purpose to valorize their utilization as local materials in road infrastructure applications. A series of compaction and direct shear tests was performed on three different classes derived from natural Chlef sand having different maximum grain sizes mixed with fly ash according to percentages ranging from 0% to 15%. The sand-fly ash mixture samples were reconstituted with water content varying between 4% and 14% for the whole experimental compaction testing program. The obtained data confirmed that the particle size and fly ash content have a significant influence on the mechanical performance (in terms of compaction response and shear strength characteristics) of sand-fly ash mixtures. Indeed, the increase of the maximum particle size and fly ash fraction induced a noticeable increase of the maximum dry density and decrease of the optimum water content for the tested sand-fly ash mixture samples. On the other hand, the obtained test results indicated clearly the impact of Dmax and FA on the shear strength response of the sand-fly ash mixtures for the fly ash content range (0%–15%) under study. The newly introduced particle size characteristics appeared as pertinent parameters to predict the compaction response and shear strength characteristics of the tested materials.

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Topics: Fly ash (66%), Compaction (52%), Direct shear test (52%)

5 Citations


Journal ArticleDOI: 10.1016/J.ENGGEO.2021.106385
Abstract: Recent population and industrial growth require innovative approaches for recycling construction materials for civil infrastructure such as railways, roads, and building foundations. This study adopts a combination of expansive black soil blended with coal wash (CW), a by-product of coal mining, to produce a resilient substructural fill for railroads. When considered individually, expansive clays and CW are prone to high swell pressure, shrinking and swelling, excessive degradation, and relatively low bearing capacity, properties that would adversely affect infrastructure. This current study is a laboratory characterisation of soil and CW mixtures in relation to Atterberg Limits, Particle Size Distribution (PSD), and X-ray diffraction spectroscopy. A mini-compaction procedure is used to assess the changes in maximum dry density and optimum moisture content. This is followed by a series of consolidated-undrained monotonic and cyclic triaxial tests of the mixtures. Our findings show that CW can reduce the plasticity, susceptibility to shrinkage, and the swell pressure of clay soil. When clay is blended with CW there is a significant improvement in the undrained shear strength, resilient modulus, and yield response before failure, as well as the number of loading cycles before failure. Furthermore, the inclusion of CW to improve the mechanical properties of soil also reduced the large amount of space needed to store CW.

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Topics: Atterberg limits (58%), Bearing capacity (53%), Population (52%)

Journal ArticleDOI: 10.1080/17486025.2021.1890233
Abstract: The hydraulic conductivity parameter of soil deposits represents an important indicator in the different soil mechanics studies (stability analysis, settlement, drainage, seepage) and it is commonl...

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Abstract: The threshold silt content is well known as a key parameter affecting the mechanical response of binary granular assemblies considering particle characteristics (size and shape). In this context, the threshold silt content (TSC) is determined from different laboratory tests based on packing density response (emax and emin versus silt content «Sc») and theoretical approaches proposed by several researchers in the specialized published literature using the characteristics of host sand and silt [emax(sand), emin(sand) , emax(silt) , emin(silt) , Gs , Gf and x]. The analysis of the recorded data indicates that the TSC derived from the (emax) curve appears more reliable than that obtained from the (emin) one. Moreover, it is found that the proposed analytical methods are suitable to quantify the threshold silt content (TSC) than that determined experimentally using the packing density (emax and emin). In addition, the test results show that the new introduced ratios [(D50s×As)/(D50f×Af)] and [(Cus×As)/(Cuf×Af)] determined based on particle characteristics (shape and size) appear as appropriate parameters for predicting the threshold silt content (TSC) of sand-silt mixture of the compiled data from the published literature as well as that of the present research related to Chlef sand, Fontainebleau sand and Hostun sand mixed with Chlef silt.

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Topics: Silt (53%), Particle (53%), Granular material (51%)

References
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32 results found


Journal ArticleDOI: 10.1061/(ASCE)1090-0241(2006)132:5(591)
Gye-Chun Cho1, Gye-Chun Cho2, Jake Dodds1, Jake Dodds2  +2 moreInstitutions (2)
Abstract: The size and shape of soil particles reflect the formation history of the grains. In turn, the macroscale behavior of the soil mass results from particle level interactions which are affected by particle shape. Sphericity, roundness, and smoothness characterize different scales associated with particle shape. New experimental data and results from published studies are gathered into two databases to explore the effects of particle shape on packing density and on the small-to-large strain mechanical properties of sandy soils. In agreement with previous studies, these data confirm that increased angularity or eccentricity produces an increase in emax and emin. Furthermore, the data show that increasing particle irregularity causes a decrease in stiffness yet heightened sensitivity to the state of stress; an increase in compressibility under zero-lateral strain loading; an increase in the critical state friction angle cs; and an increase in the intercept of the critical state line there is a weak effect on the slope . Therefore, particle shape emerges as a significant soil index property that needs to be properly characterized and documented, particularly in clean sands and gravels. The systematic assessment of particle shape will lead to a better understanding of sand behavior.

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Topics: Sphericity (55%)

1,003 Citations


Journal ArticleDOI: 10.1086/623964
Abstract: The present paper deals with the fundamental principles, conceptions, and ideas upon which some new sedimentological research methods are based.

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Topics: Roundness (geology) (52%)

836 Citations


Journal ArticleDOI: 10.1061/(ASCE)0733-9410(1992)118:1(51)
Abstract: Soils that exhibit nonassociated flow may, according to stability postulates by Drucker and by Hill, become unstable when exposed to certain stress paths inside the failure surface. Series of conventional triaxial tests on fully saturated and on partly saturated specimens were performed under drained and undrained conditions to study the regions of stable and unstable behavior. For specimens that compress and have degrees of saturation higher than critical, undrained conditions lead to effective stress paths directed within the region of potential instability, and instability was observed provided the yield surface opens up in the outward direction of the hydrostatic axis. Thus, instability occurs inside the failure surface. Instability is not synonymous with failure, although both may lead to catastrophic events. The location of the instability line is discussed. Examples of a shallow submarine slope and a nearly fully saturated steeper slope representing a tailings dam, which both should remain stable a...

... read more

Topics: Instability (57%), Slope stability (52%), Effective stress (52%)

295 Citations


Open accessJournal Article
Abstract: Soils that exhibit nonassociated flow may, according to stability postulates by Drucker and by Hill, become unstable when exposed to certain stress paths inside the failure surface. Series of conventional triaxial tests on fully saturated and on partly saturated specimens were performed under drained and undrained conditions to study the regions of stable and unstable behavior. For specimens that compress and have degrees of saturation higher than critical, undrained conditions lead to effective stress paths directed within the region of potential instability, and instability was observed provided the yield surface opens up in the outward direction of the hydrostatic axis. Thus, instability occurs inside the failure surface. Instability is not synonymous with failure, although both may lead to catastrophic events. The location of the instability line is discussed. Examples of a shallow submarine slope and a nearly fully saturated steeper slope representing a tailings dam, which both should remain stable a...

... read more

Topics: Liquefaction (58%)

286 Citations


Open accessJournal ArticleDOI: 10.1680/GEOT.11.P.062
01 Dec 2012-Geotechnique
Abstract: This paper describes a fundamental study to explore the role of particle shape in the shear behaviour of mixtures of sand and fine particles (fines) through macro-scale and grain-scale laboratory experiments together with interpretations in the framework of critical state soil mechanics and conceptual micromechanics models. Two non-plastic fines of distinct shape (angular crushed silica fines and rounded glass beads) were added to two uniform quartz sands (Toyoura sand and Fujian sand) to produce four binary mixtures. Laboratory quantification of particle shape and size was conducted for both fines and sands, and a series of undrained triaxial tests was performed to investigate the overall response of the mixed soils at different percentages of fines. One of the significant findings is that the critical state friction angle of a mixed soil is affected not only by the shape of coarse particles but also by the shape of fine particles, and this shape effect is coupled with fines content. When a small amount ...

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162 Citations