Geotextiles creep

The synthetic materials that best meet in-plane flow rate regulations are called geonets. Geonets require less space than perforated pipe or granular material, promote rapid transmission of liquids, and, because of their relatively open apertures, are less likely to clog. They do, however, require geotextile filters above them and can experience problems with creep and intrusion. 

Recently, a method for predicting the remanent life of a reinforcing geotextile was proposed [1] in which the strain to failure of a sacrificial sample was divided by the current creep rate. This requires verification. However, very few methods have so far been proposed or used for monitoring plastics in service and at the same time providing a numerical prediction of their remaining life. The reason for this is not just that the methods are likely to be expensive and complicated, but that there are few applications of plastics which can compete in risk and replacement cost with a high temperature boiler or aircraft structure. 

Fig. 4.9 Approximate limits of creep resistance for geotextiles made from different polymers.

RFcr = for reduced pore size caused by mechanical creep of material RFjn = for reduced pore space due to adjacent materials intruding into the geotextile... 

For the geotextile to provide an effective reinforcement function, it should have not only a high tensile strength, but also a high tensile modulus so that its resistance to tensile loads generated within the soil occurs at sufficiently small strains to prevent excessive movement of the reinforced soil structure. It is self-evident that decreases in these properties with time (i.e. creep behaviour) must be low, and that the polymers used should have resistance to degradation by the soil. An estimate of the anticipated reduction in strength can be determined from an analysis of creep strain versus time plots for various stress levels and a suitable reduction factor applied. 

Geosynthetic properties required for reinforced slopes are similar to those for other reinforcements. Allowable tensile strength, soil and geosynthetic friction, Eg and ga, and creep strength are the most important.The anticipated half-life of geotextile reinforcements is between 500 and 5000 years ... 

EN ISO 13431 1999. Geotextiles and geotextile-related products — Determination of tensile creep and creep rupture behaviour. 

The scope of this field test was to evaluate the possibility of using an intelligent geotextile to investigate and observe creeping slopes and landslide slopes. The... 

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