| Contents Notes |
"Geotextiles (engineering fabrics) have proven to be effective materials for solving numerous drainage and stability problems in geotechnical engineering, and they can be used to solve similar problems in the containment and disposal of solid and hazardous waste. "Geotextile" is defined as any permeable synthetic textile product used in geotechnical engineering. Important mechanical, hydraulic, and endurance properties of fabrics are discussed. Tensile strength and elongation as measured by the grab tensile test; tearing resistance as measured by the trapezoidal tear test; and puncture resistance as measured by the U.S. Army Corps of Engineers puncture test are emphasized as being the most important mechanical properties. Tests for other mechanical properties such as creep susceptibility, tear resistance, frictional and pull-out resistance with soil, and seam strength are also reviewed. The important hydraulic properties of fabrics are their ability to allow free passage of fluids, to retain soil particles (piping resistance) and to resist clogging. The equivalent opening size (EOS) and gradient ratio tests used to evaluate these qualities are discussed, as well as possible causes of the long-term reduction of fabric hydraulic flow capacity. Fabric resistance to ultraviolet light and chemicals and to biological degradation is considered . Applications of geotextiles to (1) landfill cover drains, leachate collection systems, and ground-water control systems; (2) gas venting; and (3) protection of landfill covers and waste disposal sites from surface erosion are addressed in detail. In each of these applications, design considerations, fabric requirements, and construction techniques are discussed. Model specifications for fabrics in the various applications are given. For drainage systems and erosion control, criteria for selecting fabrics based on the fabric's piping and clogging resistance are presented. Strength requirements based on the severity of the construction environment and long-term chemical/biological degradation are addressed." |
