Experimental and numerical investigations into hydraulic behaviour of coir fibre drain

Abstract

Over many decades, natural fibre bundles have been widely used for drainage and filtration applications because of their favourable hydraulic conductivity and abundance in Asian countries. In recent times, natural (biodegradable) coir and jute drains, which are environmentally friendly, have been considered in lieu of conventional geosynthetic wick drains for soft clay consolidation in Australian coastal regions. However, there is a lack of a computational framework to predict the hydraulic behaviour of fibre drains on the basis of micromechanical (fabric) characteristics. Employing computational fluid dynamics (CFD) coupled with the discrete element method (DEM) to model the hydraulic behaviour of fibrous materials has shown promise in an earlier 2016 study by Nguyen and Indraratna, which considered an idealized parallel arrangement of fibres for simplicity. This paper aims to broaden the application of the coupled CFD-DEM technique to real fibres (coconut coir) considering both nontwisted and twisted fibre bundles that have more complex porous structure. The hydraulic conductivity determined from the numerical approach is validated with the experimental results, and also compared with the analytical prediction based on the conventional Kozeny-Carmen (KC) approach. The current study shows that the CFD-DEM technique can capture well the fluid flow characteristics of a nonuniform fibrous structure, including dense twisted coir bundles.Abstract 5 Over many decades, natural fibre bundles have been used widely for drainage and 6 filtration applications because of their favourable hydraulic conductivity and abundance in 7 Asian countries. In recent times, natural (biodegradable) coir and jute drains that are 8 environmentally-friendly have been considered in lieu of conventional geosynthetic wick 9 drains for soft clay consolidation in Australian coastal regions. However there is a lack of 10 computational framework to predict the hydraulic behaviour of fibre drains on the basis of 11 micromechanical (fabric) characteristics. Employing the Computational Fluid Dynamics 12 (CFD) coupled with the Discrete Element Method (DEM) to model the hydraulic behaviour 13 of fibrous materials has shown promise in an earlier study (Nguyen and Indraratna 2016), 14 which considered an idealised parallel arrangement of fibres for simplicity. This paper aims 15 to broaden the application of the coupled CFD-DEM technique to real fibres (coconut coir) 16 considering both non-twisted and twisted fibre bundles that have more complex porous 17 structure. The hydraulic conductivity determined from the numerical approach is validated 18 with the experimental results, and also compared to the analytical prediction based on the 19 conventional Kozeny-Carmen (KC) approach. The current study shows that the CFD-DEM 20 technique can capture well the fluid flow characteristics of a non-uniform fibrous structure, 21 including dense twisted coir bundles. 22

Laboratory Investigation into Biodegradation of Jute Drains with Implications for Field Behavior

“…7a), which can reduce the porosity and discharge capacity of the drain. After being washed, the fibres that experienced the worst damage to their structure were in soil 1, while the fibres exposed to soil 3 still retain the twisting structure which plays an important role in the hydraulic conductivity of fibre drains (Nguyen and Indraratna 2017a, b). This indicates a considerable destruction that biodegradation can have on the microstructure of natural fibre drains, which can lead to the reduction in discharge capacity of drains as shown above.…”

The role of particle shape on hydraulic conductivity of granular soils captured through Kozeny–Carman approach

“…The effect that the micro-characteristics of particles have on the hydraulic behaviour of geomaterials has received considerable attention, especially in recent years thanks to advanced micro-scanning and computational methods (Matyka et al 2008;Zhou and Wang 2015;Nguyen and Indraratna 2017a). Although computer-based approaches have indicated certain advantages in predicting the hydraulic behaviour of porous geomaterials, empirical methods such as Kozeny-Carman (KC) are still used widely in practice due to their simplicity (Chapuis and Aubertin 2003;Zheng and Tannant 2017;Feng et al 2019).…”

Spreadsheet Based Business Decision Making System (Case Study in Bonorowo Land, Laren, Lamongan)

“…The part of the kenaf plant that is used is the fiber from the stem. Kenaf fiber is used as the material for making cement wall panels (Saba et al, 2015;Zhou et al, 2018), automotive structural components (Hassan et al, 2017;Verma & Sharma, 2017), fiber drain (Nguyen & Indraratna, 2017), geo textiles (Chaiyaput et al, 2014;Shirazi et al, 2019), and fiber board (Ding et al, 2015). The agricultural sector in Laren does not yet have a detailed economic analysis.…”