America, geotextiles

Geotextiles are a relatively new concept for solving problems in geotechnical engineering. They have gained wide use as not only an economical solution to these problems, but in many instances as the only viable solution to a complex engineering problem. This is evidenced by the fact that over a seven-year period from 1976 to 1983 sales of geotextiles in North America alone rose from 5 to 115 m (6 to 138 x 10 /yd ). 

Nonwoven fabrics have played an important part in the development of geotextile applications. Needle-punch fabrics manufactured from either staple fibers or spunbonded continuous filaments have found worldwide acceptance on the basis of field performance. In 2000, it is estimated that North America consumed approximately 300 million m of geotextiles (62). 

The modem history of MSW structures can be traced back to the 1960s with the advent of steel strip walls first constmcted in France. In the 1970s, modem polymeric sheet materials (geotextiles) were first employed as the soil reinforcement material in wall stmctures located in Europe and North America. Today, MSWs are ubiquitous for the earth retaining wall function. Their use and the methodologies to design these stmctures are well established and accepted. Conventional static design methods for stmctures in non-seismic areas have been extended to accommodate the additional loads that develop as a result of earthquake. 

However, this review will be somewhat different from the others in that geotextile developments in Europe (initially with nonwoven fabrics) will be presented first, with developments in America (initially with woven fabrics) following. The interchange between Europe and America up until 1977 will then be described along with developments in several other countries. Almost immediately after the first international... 

Geotextiles have been used for reinforcement in roadway systems since the early 1970s, although they are best known for their application as a separator (which is always a primary function, even with reinforcement benefits). An early project in North America was the construction of a paved roadway section over a peat bog in southern Wisconsin in 1972 (Soil Testing Services, 1972). In this project, anonwoven geotextile was used to facilitate the construction of the roadway by providing improved support over a very soft subgrade. 

Empty geotextile tubes are normally described in terms of either theoretical diameter (this occurs in Europe, Africa and Asia) or circumference (this occurs in the Americas) (Fig. 20.5(a)). However, these two parameters are of little practical use from an engineering perspective because it is the tube parameters when filled that are of engineering importance. Fig. 20.5(b) shows the filled parameters of importance, while Table 20.1 lists the approximate values of these parameters when the geotextile mbe has been filled to maximum fill height, ie, at = 0.5 Dj. The ratio of filled height to theoretical... 

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