GEOSYNTHETICS – A EFFECT OF PROCEDURES IN THE
GEOTEXTILE NEEDLE-PUNCHED
TRANSMISSIVITY WITH
ROUGH BOUNDARY CONDITIONS.
As the boundaries conditions in transmissivity tests have a influence in the drainage capacity of the geotextiles.
Transmissivity tests of non-woven fabrics like ASTM D 4716 procedures may not be adequate when laboratory results are generally to design parameters. According
GEOSYNTHETICS studios, several variables have influenced the results originally of in-plane flow tests. For all, is possible to cite: seating time, test temperature, aspect ratio, boundary surface, for others.
This work examines the transmissivity results realized in the non-woven fabrics of three different samples with some modifications in the apparatus’ boundary surface. A rough sheet was placed between tension-plate and geosynthetic interface. Needle-punched
geotextiles with 200 g/m2, 300 g/m2 and 400 g/m2 were utilized in the in-plane flow tests.
Hydraulic gradients of 0.5 and 1.0 and compressive stress varing of 10 to 200 kPa were applied in this test, according ASTM D 4716 methodology.
The finish results can prove that hydraulic transmissivity is very influenced with rough surface. The flow rate decrease for all these studied samples, showing the influence of the modificated boundary surface. Thus, more refines for researchs of the in-plane hydraulic behavior of geosynthetics are very necessary to complement the comportament of the geotextiles.
This paper was sended to Geotextiles and Geomembranes Journal in 2007.
Marcelo Ferreira dos Santos - Doctor Science in Geotecnical Engineering at Viçosa Federal University (Viçosa City, Minas Gerais State, Brazil).
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