Investigating the Relationship between Creep and Water Flow Capacity of Geosynthetics

Abstract

It has been evidenced in literature that time-dependant decrease of thickness under compressive loading affects the water flow capacity of geosynthetics. (2004) introduced a new method to estimate the long-term flow capacity of drainage geocomposites based on an estimation of the thickness reduction factor.

We propose to apply the same method to different families of geosynthetics used for drainage purposes. Two standard tests are used: EN 1897: Geotextiles and geotextile-related products — Determination of the compressive creep properties and EN ISO 12958: Geotextiles and geotextile-related products — Determination of water flow capacity in their plane.

For each geosynthetic, compressive creep properties are first determined. The long-term thickness reduction factor is derived from this first test. The stress-strain curve of the geosynthetic is then used to evaluate the stress corresponding to the reduced long-term thickness. This equivalent stress is finally applied to the water flow capacity test. A relationship is shown between creep strain and flow capacity reduction factor. We also show the magnitude of errors committed when using instantaneous water flow capacity without long-term effect correction.