Review of Long-Term Durable Creep Performance of Geosynthetics by Constitutive Equations of Reduction Factors

Abstract

In an elastic solid the strain stays constant with time and is constant and the stress decays slowly with time. The increase in strain is not linear, and the curve becomes steeper with time and also as the stress-rate is increased. The slope of the curve tends to decrease with time, but it is steeper for higher strain rates. The variation of both strain and stress with time is linear for constant stress-and strain-rate tests upon elastic materials. The final comment about the compressive creep test and data interpretation is as follows: (1) Description of the creep mechanism of the geosynthetics (exactly not compression but perpendicular compression) is very important because the creep mechanism of tension and compression is quite deferent. (2) To reduce the specimen-to-specimen, many ramp-and-hold (in the case of tension creep: 1 h) tests are recommended. (3) Loading rate is also important because it make initial strain value. To check the nonaffected loading rate, prior to the main creep test, some kind of short-term test is needed. (4) The method to assess the reduction factor by creep also will be reviewed because the value will be changed according to the applied load.

FEM model for analysing the interaction of a geomatrix with a subsoil

“…In advanced numerical analyses, various types of material models (e.g. Maxwell and Voight models) are used, which are capable of describing rheological properties of materials (changes of stress-strain state over time), including polymeric ones, from which geosynthetics are made [5], [18], [19], [20], [21], [22], [23]. However, in practice, the values of the parameters of these models are not estimated, and moreover, a typical engineer is not prepared in terms of knowledge of mechanics to solve such problems.…”