05-28-1991 Council Packet - Laserfiche WebLink

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8 An Overview of Geosynthetics Chap. 1 enlaroeo view Of SEQTEXTILE fibers HONOn MONOflLAMCNT YARN (MulllfilORMl) STARLC STARIX 'YARN Figure 1.2 Types of fibers used in the construction of geotexules. of specific denier* from the spinneret in a large ropelike bundle called a tow. A tow can contain thousands of continuous filaments. These bundles are then crimped and cut into short staple lengths of 1 to 4 in. The shon fibers, or staple, are then twisted or spun into longer fibers (yams) for subsequent fabric manufacturing. The last type of fiber to be mentioned is made completely differently from those discussed above. These fibers, called slit (or split) film, are made from a continuous sheet ol the polymer and then cut into fibers by knives or lanced by air jets. The resulting ribbonlike fibers will be referred to as slit-film fibers. Thus the principal fibers used in the construction of geote.xtiles are as toliows (see Figure 1.2): Monofilament Multifilament Staple Staple yam Slit film These resulting fibers, or yams as they would be referred to in the textile industry, are now made into fabrics. The basic manufacturing choices are woven, nonwoven, or knit, which are each shown in Figure 1.3. although knit fabrics are seldom used as geo textiles. The woven fabrics are made on conventional textile weaving machinery' into a wide variety of fabric weaves. Kaswell [14] gives an excellent review of weaving tech nology in which each of the various fabric weaves is clearly illustrated. Variations are many and most have some, or a major, influence on the physical, mechanical, and hy draulic properties of the fabric. The manufacture of nonwoven fabrics is very different from that of w'oven fabrics. Each nonwoven manufacturing system generally includes four basic steps; fiber prepara- ■Denier is defined as the u-icht in grams of 9000 m of yam. The related textile term weight in grams of 1000 m of yam tex." IS the Lii^