Effects of Fines Content on Hydraulic Conductivity and Shear Strength of Granular Structural Backfill

Author(s):  
Brian W. Gomez ◽  
Mandar M. Dewoolkar ◽  
John E. Lens ◽  
Christopher C. Benda
2021 ◽  
Vol 80 (10) ◽  
pp. 7899-7919
Author(s):  
Jianhua Shen ◽  
Xinzhi Wang ◽  
Xing Wang ◽  
Ting Yao ◽  
Houzhen Wei ◽  
...  

1988 ◽  
Vol 68 (4) ◽  
pp. 763-774 ◽  
Author(s):  
LINNELL M. EDWARDS

Soil physical characteristics were examined at depth intervals of 0–15 and 15–30 cm over three slope positions (top-, mid-, and bottom-slope) for three cropping sequences (hay-barley, cereals-barley, and potato-barley). Hydraulic conductivity was a significant (P ≤ 0.05) 40–50% greater at top-slope than mid- or bottom-slope, and aggregate stability percentage was a significant 6–7% greater at bottom-slope than mid- or top-slope when the soil aggregates were pretreated by freezing and thawing (freeze/thaw). Under the potato-barley sequence shear strength, penetration resistance and bulk density were significantly greater than any other sequence by up to 29, 21 and 15%, respectively; while hydraulic conductivity and maximum penetration depth were, respectively, up to 65 and 28% lower than any other sequences. Under hay-barley, hydraulic conductivity and aggregate stability (freeze/thaw) were, respectively, up to a significant 82 and 10% greater than any other sequence. There was, therefore, significantly more compaction under potato-barley and more soil physical enhancement under hay-barley than other respective sequences. Disease severity was up to 55% greater at bottom-slope than at mid-slope or top-slope for Birka barley, which also showed a significant linear decrease (r2 = 0.89) in yield with increasing shear strength. Yield of Perth barley showed a significant linear increase with increasing soil depth (r2 = 0.92) and clay-silt content (r2 = 0.78). Key words: Aggregate stability (freeze/thaw), crop rotation, penetration resistance, shear strength, barley, potatoes, hay


2020 ◽  
Vol 42 (1) ◽  
pp. 18-35 ◽  
Author(s):  
Djamel Bouri ◽  
Abdallah Krim ◽  
Abdelkader Brahim ◽  
Ahmed Arab

AbstractThis paper presents a laboratory study of the combined effect of the water content and fines content on the mechanical behaviour of Chlef sand in a medium dense state (RD = 65%) and dense state (RD = 80%). Several mechanical parameters were evaluated such as shear strength, cohesion and friction angle at different water content w = 0, 1, 2 and 3% and different fines content Fc = 0, 10, 20, 30 and 40%. The test results showed that the shear strength of Chlef sand decrease with the increase fines content Fc = 0 to 40%, our tests result also showed that the water content has a significant influence on the shear strength which decreases with the increase in the water content w = 0 to 3%. The fines content and the water content have a significant influence on the mechanical parameters c and φ. Cohesion increases with the percentage of fines and decreases with the increase of the water content while the friction angle decreases with the increase the fines content and the water content.


Author(s):  
Jiying Fan ◽  
R. Kerry Rowe ◽  
Richard W.I. Brachman

Microstructure showing the involvement of the fine and coarse grains in the soil skeleton is evaluated. Incremental loading tests using a stress-dependent permeameter are conducted on the mixtures of poorly graded sand and nonplastic fines originating from tailings. The results are compared with the published data of various tailings. It is shown that increasing the fines content from 0 to 100%, the involvement of the fine and coarse components of soil skeleton can be classified into four categories: no fines involvement (<10% fines), fines partially involved (10% —35% fines), increasing cushioning effect surrounding the coarse (35% — 40% fines), and constant cushioning effect (> 40% fines). At the same consolidation stress, the void ratio, e, rapidly decreases for fines less than 30%, then almost remains constant between 30% and 50% fines, and gradually increases for fines exceeding 50%. The hydraulic conductivity, k, decreases more than 20-fold as the fines content increases from 12% to 50%, then remains constant. k is proportional to [e3/(1+e)]A and inversely proportional to S2, where A is a factor describing the effect of particle angularity and S is the specific surface. Finally, the influence of fines content on the seepage-induced internal stability is discussed.


2015 ◽  
Vol 18 (2) ◽  
pp. 149-156 ◽  
Author(s):  
Mohamed Bensoula ◽  
Hanifi Missoum ◽  
Karim Bendani

<p>This study uses experimental triaxial tests with monotonic loading to develop empirical relationships to estimate undrained critical shear strength. The effect of the fines content on undrained shear strength is analyzed for different density states. The parametric analysis indicates that, based on the soil void ratio and fine content properties, the undrained critical shear strength first increases and then decreases as the proportion of fines increases, which demonstrates the influence of fine content on a soil’s vulnerability to liquefaction. A series of monotonic undrained triaxial tests were performed on reconstituted saturated sand-silt mixtures. Beyond 30% fines content, a fraction of the silt participates in the soil’s skeleton chain force. In this context, the concept of the equivalent intergranular void ratio may be an appropriate parameter to express the critical shear strength of the studied soil. This parameter is able to control the undrained shear strength of non-plastic silt and sand mixtures with different densities.</p><p> </p><p><strong>Resumen</strong></p><p>Este estudio utiliza evaluaciones experimentales triaxiales con cargas repetitivas para desarrollar relaciones empíricas y estimar la tensión crítica de corte bajo condiciones no drenadas. El efecto de contenido de finos en la tensión de corte sin drenar se analizó en diferentes estados de densidad. El análisis paramétrico indica que, basado en la porosidad del suelo y las propiedades del material de finos, la tensión de corte sin drenar primero se incrementa y luego decrece mientras la proporción de finos aumenta, lo que demuestra la influencia de contenido de finos en la vulnerabilidad del suelo a la licuación. Una serie de las evaluaciones se realizó en  mezclas rehidratadas y saturadas de arena y cieno. Más allá del 30 % de los contenidos finos, una fracción del cieno hace parte principal de la cadena de fuerza del suelo. En este contexto, el concepto de porosidad equivalente intergranular puede ser un parámetro apropiado para expresar la tensión crítica de corte del suelo estudiado. Este parámetro nos permite controlar la tensión de corte sin drenar de cieno no plástico y mezclas de arena de densidades diferentes.</p>


2019 ◽  
Vol 92 ◽  
pp. 06001
Author(s):  
N'guessan MoÏse Kouakou ◽  
Olivier Cuisinier ◽  
Farimah Masrouri ◽  
Emmanuel Lavallée ◽  
Tangi Le Borgne

The determination of the mechanical properties of soils containing particles larger than the allowable size of standard laboratory equipments is complex. It is indeed necessary to remove the coarsest fraction to carry out the tests. This scalping poses a problem of reliability of the results at the scale of the structure. Parallel gradation is the method commonly used for estimating the shear strength of heterogeneous granular soils from tests on their finer fraction. However, the effect of high fines content on the estimation of shear strength by this method is not well understood. The results of this study show that the parallel gradation method can predict the friction angle of the initial soil with high fines content when the modelled soil has a similar skeleton as the initial soil. However, the cohesion of the initial soil is overestimated.


2013 ◽  
Vol 831 ◽  
pp. 331-335 ◽  
Author(s):  
Ren Peng ◽  
Yu Jing Hou ◽  
Xue Dong Zhang ◽  
Qing Lei Sun

A model waste mixing with kaolin, sand, and peat was developed. The physical properties of the waste were compared with the real municipal solid waste (MSW). The influence of unit weight on compression factor, shear strength, and saturated hydraulic conductivity was acquired. In addition, the homogeneous of the soil model was detected using the IWHR 450g-ton centrifuge and the newly developed centrifuge-robot.


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