Filtration behaviour of granular soils under cyclic load

Closure to “Internal Stability of Granular Filters under Static and Cyclic Loading” by Jahanzaib Israr and Buddhima Indraratna

“…1 shows the particle size distribution (PSD) curves for the cyclic filtration data adopted for the verification of the proposed model in the paper under discussion. As is clearly shown, these soils included a broadly graded sandy gravel C45 (Kamruzzaman et al 2008), five gravelly sands [C15 and C25 from Kamruzzaman et al (2008), H-12 from Haque et al (2007), Ip-12 from Chung Ip et al (2012), and KF from Kabir et al (2006)], and a uniform medium sand BS from Alobaidi and Hoare (1998). The writers agree with the discussers that the soils exhibiting cohesive characteristics should be examined by the relevant methods.…”

“…Thus far, the paper under discussion is probably the first and only study that has presented experimental results of internal stability analysis under cyclic loading, and the authors could only find a very limited number of studies that have indirectly addressed the internal stability of granular filters under cyclic conditions (Chung Ip et al 2012;Kamruzzaman et al 2008;Haque et al 2007;Kabir et al 2006;Alobaidi and Hoare 1998). These data included information such as time histories of effluent turbidity and permeability, pretest and posttest PSD curves (Chung Ip et al 2012;Kamruzzaman et al 2008;Haque et al 2007;Kabir et al 2006), and the type of seepage-induced failure (Alobaidi and Hoare 1998). The authors could conveniently analyze these data for internal instability potential of soils based on the rationale of Israr et al (2016), as explained in the following section.…”

“…According to the discussers, the existing criteria for noncohesive soils including the current method have been used by the authors for assessing the internal stability of some of the cohesive materials; 2. The discussers argue that the effectiveness of the filters has no relationship with the internal stability, and therefore the existing cyclic filtration data from the literature (e.g., Haque et al 2007;Kamruzzaman et al 2008;Chung Ip et al 2012;Alobaidi and Hoare 1998) cannot be analyzed for determining their potential for internal instability; and 3. The existing geometrical methods for internal instability assessments of granular soils are not applicable for the composite materials such as soils with geotextile and geocomposite inclusions.…”

Caractérisation des matériaux constitutifs de plate-forme ferroviaire ancienne

“…On peut en déduire que les particules fines de la couche intermédiaire proviennent, d'une part, du sol support à cause du phénomène de remontée de fines et, d'autre part, de la dégradation du ballast (calcite et quartz) due au passage des trains. En effet, l'état hydrique de la plate-forme, associé à la sol licitation dynamique causée par la circulation du train, influence forcement le phénomène de remontée des fines (Kabir et al, 2006 ;Haque et al, 2007 ;Kamruzzaman et al, 2008 ;Indraratna et al, 2007). La dégradation des ballasts due au trafic des trains a été étudiée par Li et Sclig, 1995 ;Indraratna et al, 2005 ;Lackenby et al, 2007 ;Karraz, 2008.…”

“…Pourtant, ces travaux sont souvent réalisés sur les sols utilisés dans des remblais ou des travaux routiers. Concernant les travaux de recherche sur les plates-formes ferroviaires, en plus des recherches sur le sol support soumis au chargement dû à la circulation des trains (Li et Selig, 1998a, b ;Okada et Ghataora, 2002 ;Choudhury et al, 2008 ;Indraratna et al, 2006), d'autres phénomènes spécifiques ont été étudiés : a) la remontée du sol support dans les couches supérieures (Alobaidi et Hoare, 1996 ;Kabir et al, 2006 ;Haque et al, 2007 ;Kamruzzaman et al, 2008 ;Indraratna et al, 2007) ; b) le développement de la surpression intersti tielle à la surface entre le sol support et la sous-couche (Alobaidi et Hoare, 1996). Les travaux sur les caracté ristiques hydromécaniques des sols intermédiaires des plates-formes anciennes restent rares.…”