Geotekstil-zemin filtre sistemi için deneysel bir çalışma

Filters have been used in earth structures such as retaining walls, earth dams etc. to prevent the loss of particles induced by seepage of water. Traditionally granular filter materials are used, however, they are becoming more difficult to obtain and transport to the construction site and transportation of granular material raise the cost of construction and carbon footprint of the project. Therefore, the need for an alternative filter material arises, and geotextiles can be considered as one of the best options. The experimental investigation was conducted in the laboratory to evaluate the Gradient Ratio test method for steady unidirectional flow through non-woven geotextiles. Tests were performed according to specification of ASTM D5101. Kayseri Clay that is a sample dam clay according to specification of State Hydraulic Works (DSI) was used as a base soil to reflect the actual clay core earth fill dam behavior, and two non-woven geotextiles, having different openin area and thicknes, were used. Also, the granular filter-clay combination was tested to compare geotextile filter and granular filter filtration behavior. It has been found that the stabilization in the permeability of system was greatest and fastest for the geotextile that had smaller opening area, and amount of loss of fines was detected in the case of having larger opening size and thinner geotextile system.Furthermore, using two-layers of geotextile in the system showed better filtration performance. The filtration performance of the geotextile was affected by the compaction state of the base soil. The denser compaction of clay positively affected the filtration performance. Finally, the system was analyzed in three zones of permeameter. It is observed that the system permeability behavior was very similar to permeability of soil layer next to geotextile. The results of this study are believed to help further understand the use of non-woven geotextiles in earth dams as filter material.