Geosynthetics examples

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... 

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. 

Geosynthetics with high tensile strength and stiffness such as geogrids, woven tapes/strips are used in reinforcement applications. Examples are reinforced soil walls, reinforced steep slopes, slope repair by reinforced soil, basal reinforcement at the base of embankments on soft ground or embankments over piled foundations, as illustrated in Figure 5.6. 

Fig. 3.25. Examples of vertical displacement vs. time curves of a geosynthetic clay liner specimen as monitored by displacement sensors (Thies 2002 Muller et al. 2004)...

Case histories systematic quantitative and qualitative evaluation of previous experience reference (Hutten 1992) provides an example for geomembranes and the book Geosynthetic Case Histories (Raymond and Giroud 1993) for geosynthetics in general,... 

Figure 8.13 Example of apparatus for measuring in-plane geotextile permeability. Geosynthetics Laboratory of CESI SpA in Italy.

This concept was used, for example, to estimate the induction time of HOPE geomembranes by Hsuan and Koemer (1998). OIT and its HP application via HP-OIT testing are employed in specifications for HOPE, linear low-density polyethylene, and PP geomembranes (see Geosynthetic Research Institute standard specifications). 

Figure 9.15 Example of compressive creep test results of a geosynthetic drain at various load levels.

Short-term reductions in flow are generally measured via short-term hydraulic testing of the geosynthetic drain (examples are ASTM D4716 and ISO 12958). However, the time-dependent compression and intrusion will lead to a reduction in flow capacity and are critical to the long-term determination of flow. Indeed, collapse of the core will lead to significant flow reduction. 

The versatility of geotextiles as separators can be coupled well with other geosynthetics and even with soil to form a composite material. Common examples are as follows ... 

The use of geotextiles to reinforce soft foundation soils has progressed from the earliest applications some 40 years ago to the current status of widespread use and success. This chapter presents three major application areas (1) basal reinforcement, (2) geotextile-encased granular columns, and (3) geosynthetic piled foundations. In addition to the descriptions, elements of design, and information on performance, a specific project example was given for each topic. Further advances can and should be made, but we beheve that the current state of the practice in the selected applications is properly reflected here. 

Erosion control Geotextiles reduce soil erosion caused by rainfall impact and surface water runoff. For example, temporary geosynthetic blankets and permanent lightweight geosynthetic mats are placed over the otherwise exposed soil surface on slopes. Geotextile silt fences are used to remove suspended particles from sediment-laden runoff water. Some erosion control mats are manufactured using biodegradable wood fibers and related biomass. 

---