Geotextile bags

In ports with smaller depths where the soft bottom (similar to sand) effect is required the mattress of geotextile bags filled with sand on geotextile sheet are used. The reason is the required under keel clearance. It should be 0.45 m for sand and 0.6 for rocks and stone riprap. 

Examples of expenses bear for the inspections and repair of mattress of geotextile bags filled with sand and pinned together, placed along the steel Larsen type tight wall are presented in Table 2 (Abramowicz-Gerigk, 2014). 

Three types of geotextile containment units are used in marine engineering, differentiated on the basis of shape and volume geotextile bags, geotextile tubes and geotextile containers (Fig. 20.2). 

Figure 20.2 Types of geotextile containment units used in marine engineering, (a) Geotextile bags, (b) geotextile tubes and (c) geotextile containers.

Geotextile bags are commonly pattern placed in marine structures to achieve greater stability than if they were randomly placed. Pattern placement greatly increases resistance to wave forces and results in a tight structure that can resist erosion. 

Geotextile bags are used for a range of marine engineering applications. These include revetments (Fig. 20.3(a)), groins (Fig. 20.3(b)), artificial reefs (Fig. 20.3(c)), slope buttressing (Fig. 20.3(d)), scour prevention (Fig. 20.3(e)) and temporary protection dykes (Fig. 20.3(f)). Some of these applications are discussed in further detail later in this chapter. 

Figure 20.11 Three different revetment structures using geotextiles. (a) Rock revetment utilising geotextile filter, (b) revetment utiUsing geotextile bags and (c) revetment utilising geotextile tubes.

Geotextile bags are also used for revetment stmctures in marine environments (Fig. 20.11(b)). Here, the bags act as the primary armour protection, with stability behaviour provided by the mass-gravity of the bag units and their pattern placement. Fig. 20.13 shows a geotextile bag revetment in a marine environment in which the bags have been placed in a specific pattern-placement layout to maximise stability. 

Figure 20.13 Geotextile bag revetment. Courtesy Geofabrics Australasia.

Fig. 20.14 presents potential failure modes that should be assessed for geotextile bag revetments. These deal with external stability (Fig. 20.14(a)), internal stability (Fig. 20.14(b)) and durability (Fig. 20.14(c)). Each of these will be discussed in further detail. 

Assessment of the internal stability of geotextile bag revetments (Fig. 20.14(b)) should include details such as the required geotextile skin robustness (to prevent... 

Figure 20.14 Different stability and integrity modes of failure for geotextile bag revetments, (a) External stabiUty, (b) Internal stability and (c) durabibty.

Geotextile tube revetments have much in common with geotextile bag revetments (Section 20.3.3) except that the units are of much greater mass-gravity and are continuous in a longitudinal direction. This makes them considerably more stable even when subjected to extreme weather events. 

Geotextile tube revetments are designed similar to geotextile bag revetments in assessing the possible modes of failure (Fig. 20.14). Bezuijen and Vastenberg (2012) provide relationships for assessing geotextile tube stability when subjected to external water forces. 

Figure 20.40 Use of geotextile bags for scour protection around monopile foundations. 

Figure 21.1 Examples of geotextile flexible forming systems, (a) Large geotextile bags for coastal erosion control (compliments of NAUE). (b) Geotextile containers for transport of harbor sediment (compliments of Ten Cate), (c) Geotextile tubes for harbor sediment dewatering and decontamination (authors).

GRI-GT15, 2009. Standard Test Method for Pillow Test for Field Assessment of Fabrics/ Additives Used for Geotextile Bags, Containers and Tubes. Geosynthetic Institute, Folsom, Pennsylvania, USA. 

Koerner, R.M., Koemer, G.R., 2009. Performance tests for selection of fabrics and additives when used as geotextile bags, containers and tubes. Geotextile Testing Journal 33 (3), 236-242. 

Geotextile bags for eutrophication and waste management remediation... 

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