Soil Testing Equipment

Geosynthetics include exclusively manmade polymeric products such as geotextiles, geogrids, geonets, geomembranes, geosynthetic clay liners, and geocomposites. The term “geosynthetic” is used in favor of
geotextiles and geofabrics because 

five main functions: separation, reinforcement, filtration, drainage, and containment (hydraulic barrier). However, in most applications, geosynthetics typically perform more than one major function.

Some basic standards used for geotextiles are adopted from the textile industries. However, geotechnical engineers realized the deficiencies and started to develop the standards relevant to their applications. The American Society for Testing and Materials (ASTM) is one developer of standardized testing procedures for
different geosynthetics. Most testing standards adopted or developed in other countries are outgrowths of ASTM standards. The Geosynthetic Research Institute (GRI) also provides testing standards to serve industrial needs, especially when related ASTM standards have not been developed. GRI standards are usually removed as related ASTM standards become available. ASTM standards, developed under Committee D35 for Geosynthetics, are listed in the Appendix. These standards were developed under several
subcommittees: terminology, mechanical properties, endurance properties, permeability and filtration, geosynthetic clay liners, geosynthetic erosion control, and geomembranes. New standards are constantly being developed. Details of test standards are published in ASTM (2000).

While ASTM standards are index tests, many civil engineering designs and applications require the geosynthetic materials to be tested with site-specific soils, with the testing conditions representing those in the field. These kinds of tests are known as performance tests.

Different organizations, agencies, and manufacturers provide design guidelines for geosynthetic applications. These design methods are determined by cost, specification (design by specification), or function (design by function). Public agencies have widely adopted the design-by-specification method. The minimum required value of the geosynthetic properties used in a particular application is specified. In the design-by-function method, the primary function of the geosynthetic material is identified. The available and required value of the particular property for that function is assessed to give a factor of safety (FS):

FS = allowable property from testing / required property for design

Designs require a factor of safety greater than unity to account for various uncertainties.