Th. Kossendey, LGA-Geotechnical Institute, Nürnberg, Germany
G. Karam, DuPont de Nemours, Luxembourg
Extract:
The long-term filter performance of 5 Geotextiles differing in permeability, thickness, mass per unit area and type of polymer was studied experimentally in large permeameters using three different soils. In a series of three tests, Geotextile samples of 500 mm diameter were submitted to steady state seepage under different hydraulic gradients for periods of between 6 and 24 months. In the first two performance tests, the water flow was in direction of gravity. The third test series simulated the case of an upward water flow. Although the Geotextiles differed in their physical parameters, their filtration performance was similar and satisfied the requirements for stable filter performance. A detailed microscopic investigation into the soil structure immediately above the Geotextiles confirmed the formation of a bridging network of particles acting as a naturally graded soil filter.
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