Geotextiles and geotextile containment units used in marine engineering

2 Geotextiles and geotextile containment units used in marine engineering 

GeotestUes. http 7/dx.(laLorgnOLl01 at978.0. S-1002214.00020.6 Copyright 2016 Elsevier Ltd. All rights reserved. 

Woven polypropylene geotextiles are characterised by medium pore sizes (0.3—0.6 mm) with medium water flow (15—50 L/m per s), which makes them effective filters for sands and sandy soils. They have relatively low maximum elongations (10—20%), which enables them to maintain a stable stractural shape. They also have good tensile strength (80—200 kN/m), which enables them to be used in stractural roles and to be installed at significant water depth if required. 

Nonwoven geotextiles are formed by the bonding of random arrays of synthetic fibres (see chapter Geotextile manufacturing processes). Fig. 20.1(b) shows the typical random stmcture of nonwoven geotextiles which commonly are composed of polypropylene fibres but can also be composed of polyester fibres. 

Composite geotextiles are formed by the integral combination of two geotextile types into a single (composite) geotextile material nonwoven plus nonwoven or woven plus nonwoven. The resulting composite stmcture exhibits the positive attributes of both component parts. Fig. 20.1(c) shows the stmcture of a woven—nonwoven composite geotextile. 

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