Pilot Scale Field Test for Natural Fiber Drain

A numerical approach to modelling biodegradable vertical drains

“…Natural fibres do not only have preferable engineering characteristics such as high hydraulic conductivity and tensile strength, they are also biodegradable over time, so they are used to create natural fibre drains (NFDs). Although many previous studies (Lee et al 1994;Jang et al 2001;Lee et al 2003;Asha and Mandal 2012) report that NFDs can perform as well as polymeric prefabricated vertical drains (PPVDs), some indicate that critical degradation of natural fibres can occur as they are exposed to adverse environmental and geotechnical conditions (Miura et al 1995;Kim and Cho 2008;Saha et al 2012). While conventional design methods (Barron 1948;Hansbo 1981;Rujikiatkamjorn and Indraratna 2009) normally assume constant drain properties of drains over time, overly swift degradation of NFDs can result in a significant loss in their engineering characteristics, leading to a negative effect on the soil consolidation progress.…”

“…For example Miura et al (1995) show serious degradation of jute drains installed in Ariake clay where the tensile strength of drains decreased by approximately 80% over a short period of 128 days. Kim and Cho (2008) investigated the degradation of natural fibre drains over different seasons in the field and concluded a considerable reduction in the tensile strength of fibres in warm periods. Indraratna et al (2016) addressed how the rapid degradation of NFDs could affect the consolidation process using an analytical approach.…”

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

“…Soil improvement using natural prefabricated vertical drains (NPVDs) (also known as natural fibre drains) has been carried out in several regions, especially in South and Southeast Asia, ever since the first NPVD was introduced by Lee et al (1987). Many field observations (Lee et al 1994;Lee et al 2003;Kim and Cho 2008) have shown that NPVDs with favourable engineering characteristics such as excellent discharge capacity and resistance to deformation, i.e., bending and kinking are a viable alternative to synthetic prefabricated vertical drains (SPVDs) made from polymeric materials which are seen as possibly having an adverse effect on the natural environment (Gregory and Andrady 2003). However, many of these applications were in inert soils, which may not harm the engineering properties of the drains, so their biodegradation characteristics have not received any serious attention.…”

“…While raw natural fibres such as jute and coir can be used to make NPVDs which are normally band-shaped with a number of coir cores wrapped by layers of jute geotextiles (Fig. 1a), the straw which is a sub-product of rice fields and very popular in Asian countries is used to create circular drains, as Kim and Cho (2008) describe. This study shows that straw fibre drains have a lower discharge capacity than jute fibre drains but they can still discharge excess pore pressure at an acceptable rate.…”

The permeability of natural fibre drains, capturing their micro-features

“…Note that more lignin means that the fibre can resist biodegradation better. The durability of natural fibres also depends on environmental conditions such as humidity, temperature, acidity and the biological properties of the soil (Kim and Cho, 2008;Saha et al, 2012). Other natural fibres such as straw, bamboo and hemp are abundant in many agricultural regions such as Vietnam and Thailand.…”