engleski

INVESTIGATIONS OF THE HYDRAULIC PROPERTIES OF GEOTEXTILES

Geotextiles as a very large subgroup of technical textiles, are specially designed for a wide range of civil engineering applications, including ground works, soil drainage and filtration, soil reinforcement and erosion control. Hydraulic properties of geotextiles are, beside mechanical characteristics, also very important. Since one of the most important functions of geotextiles is filtration, it is necessary to be familiar with their water permeability. It is as well necessary to distinguish among the permeability vertical to the plane of geotextiles, or permissivity, and water-permeability along the plane of the material, or transmissivity, which is of key importance in drainage. In road construction, and especially in the construction of tunnels, when solving problems of hydroinsulation, it is desirable that geotextiles have an anisotropic structure in order to separate underground water following the arch of the tunnel. In this way excessive loads may be prevented, imposed by large quantities of water onto the hydroinsulating foils and the concrete layer. Before using geotextiles, it is necessary to establish their characteristics, i.e. their quality. There are definite methods of water-permeability examinations, stipulated by numerous national and international standards. Modified procedures of transmissivity examination, by measuring the flow rate of oil of certain viscosity through geotextiles at various pressures and at different modes of result interpretation, are applied and compared. The results and information obtained on isotropy of the materials may be used as a basis for the selection of particular types of geotextiles in practice.

geotextiles; water-permeability; isotropy of structure

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