Geosynthetics functions

IGS Educational Resource, Geosynthetics Functions, 2010. International Geosynthetics Society. Jenner, C.G., Paul, J., 2000. Lessons learned from 20 years experience of geosynthetic reinforcement on pavement foundations. In EuroGeo 2000 Conference Proceedings. Bologna, Italy, pp. 421—425. 

Geosynthetic functions in erosion and sediment control applications... 

The design of cover systems is site-specific and depends on the intended function of the final cover—components can range from a single-layer system to a complex multilayer system. To minimize percolation, conventional cover systems use low-permeability barrier layers. These barrier layers are often constructed of compacted clay, geomembranes, geosynthetic clay liners, or combinations of these materials. 

In more recent applications, several types of ET cover designs also have incorporated synthetic materials, such as geomembranes, which are used to enhance the function of minimizing water into the waste. For example, the Operating Industries Inc. Landfill in California has incorporated a soil layer with a geosynthetic clay liner in the design. The cover system for this site will reduce surface gas emissions, prevent oxygen intrusion and percolation, and provide for erosion control.68... 

Key words geosynthetics, geotextiles, geocomposites, structures, properties, functions, multifunctionality, applications. 

Most non-textile geosynthetics are used with geotextiles, and therefore it is more informative to consider the functions, structures and properties of all the material types. This should aid the reader s understanding of the role played by geotextiles, whether employed with the other materials or as their substitutes in the various geotechnical applications described later as examples. 

Similar to the filtration function, the requirements for drainage are soil retention, adequate flow capacity, and long term soil-to-geotextile flow equilibrium, in respect of minimum clogging of the pore spaces. Apart from the flow capacity within the plane of the geosynthetic material, the other aspects have been dealt with above. We will therefore now consider the inplane flow characteristics. 

Functions of geosynthetics containment (fluid barrier) and protection... 

Although in many applications it is possible to identify one dominant or primary function, geosynthetics usually perform one or more essential secondary functions. 

Geosynthetics have been used in new road construction in various ways to minimise the previousiy mentioned probiems as weii as in the maintenance of existing paved roads (overiays appiied to strengthen existing pavements). In this category of application the two principal roles for geosynthetics are separation/filtration, and reinforcement. The use of geosynthetics to perform these functions in unpaved and paved roads is discussed in Section 5.1.3.1 and 5.1.3.2. 

Fig. 5.1. Ageing impairs functional reserves. Depending on the level of action, failure occurs sooner or later. Slow ageing or large functional reserves result in long service lives. Applying a factor of safety (FS) to the resistance means to implicitly define a certain service lifetime of the constmction product. The questions whether the tme service lifetime of a certain geosynthetic product and its service lifetime with respect to the choice of FS are actually larger than the required service life are seldom considered explicitly in geotechnical design...

Table 19.1. Design requirements for geosynthetics with a filter and separation function.

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