Geotextile containers

The fifth example study has shown that using sand encapsulated in geotextile containers for the core of rubble mound breakwaters, which is about one order of magnitude less permeable than a conventional core made of quarry run, may provide many advantages. This is particularly the case when rock material (quarry run) is... 

C. R. Lawson, Geotextile containment International perspectives, Proc. Seventeenth GRI Conf., Geosynthetic Institute, Philadelphia, USA, December (2003), pp. 198-221. 

S. Restall et al., Australian and German experiences with geotextile containers for coastal protection, 3rd EuroGeo, Munich, Germany (2004). 

Table 21.2. Types of geotextile containments used in coastal engineering.

Most of the applications of geotextile containment in coastal engineering belong to this type of shore protection i.e., the containment is built directly along the shoreline to prevent erosion and to stabilize a beach-dune system during storm surge (Fig. 21.7). For this purpose, different types of containments have been applied, very often as a last defense line in combination with beach nourishment. 

Fig. 21.8. Geotextile containment for dune reinforcement, Sylt/Germany (extended and modified from Ref. 26).

For this purpose it is necessary to address the following aspects (i) hydraulic permeability of GSC-structures and its effect on the stability, (ii) wave loads and identification of the most critical loading case and location of the containers, (iii) internal movement of sand fill and its effect on the stability, (iv) effect of the friction angle between geotextile containers on the stability, and (v) effect of the container deformations on the stability. 

The effect of the deformations of the GSCs on the hydraulic stability rapidly increases with the severity of wave attack, depending on the size and sand fill ratio of the containers as well as on the degree of exceedance of the wave loads required for the inception of the internal movement of the sand fill. Besides, the effect on the hydraulic stability, the internal sand movement in submerged geotextile containers may lead to a substantial reduction of the height of GSC-structures (up to about 10%) when subject to severe wave attack. 

C. R. Lawson, Geotextile containment for hydrauhc and environmental engineering, Proc. Ceosynthetics Int. Conf. (Mitchpress, Rotterdam, 2006), pp. 1-48. 

H. Oumeraci, M. Hinz, M. Bleck and A. Kortenhaus, Sand-filled geotextile containers for shore protection, Proc. COPEDEC, Colombo, Sri Lanka (2003). 

S. J. Restall, W. P. Hornsey, H. Oumeraci, M. Hinz, F. Saathoff and K. Werth, Australian and German experiences with geotextile containers for coastal protection, Proc. Euro-Geo 3, Munich, Germany (2005), pp. 141-146. 

F. Saathoff, H. Oumeraci and S. Restall, Australian and German experiences on the use of geotextile containers, Geotex. Geomem 25, 251-263 (2007). 

Geotextiles and geotextile containment units used in marine engineering... 

Sand fill is normally used for geotextile containment units in marine engineering applications because it is permeable, it is stable when the sand fill is dense, and it does not undergo volume changes with time, ie, settlements. Fine-grained fills stabilised with cement or polymer have also been used in geotextile containment units for marine applications however, this is a new, emerging development and is not discussed further in this chapter. 

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.

After Lawson, C.R., 2008. Geotextile containment for hydraulic and environmental engineering. Geosynthetics International 15, 384—427. 

Geotextile containers (Fig. 20.2(c)) are large-volume units that are filled above water and then positioned and deposited at water depth by means of a split-bottom barge. Typical container volumes range from 80 to 700 m. ... 

Because they are tubular in shape, they do not require sealing once filled, which is a major benefit with this form of geotextile container. 

Geotextile containers are used for a range of marine engineering applications which require placement of the units at water depth. These include offshore breakwaters (Fig. 20.10(a)), containment dykes (Fig. 20.10(b)), artificial reefs (Fig. 20.10(c)) and slope buttressing (Fig. 20.10(d)). Some of these applications are discussed in further detail later in this chapter. 

Figure 20.10 Marine engineering applications of geotextile containers, (a) Offshore breakwaters, (b) containment dykes, (c) artificial reefs and (d) slope buttressing.

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