UTILIZATION OF NON-WOVEN TEXTILES FOR DRAINAGE: APPLICATION TO SHOULDERS OF FINE SOILS FOR CONSOLIDATION
UTILISATION DES TEXTILES NON-TISSES POUR LE DRAINAGE. APPLICATION AUX REMBLAIS DE SOLS FINS EN COURS DE CONSOLIDATION
This report concerns the study of non-woven fabrics with a view to their utilization as a drainage layer in fine soil embankments with a high water content. The first part deals with the characteristics of a number of fabric sheets. Fabric sheets differing in nature and structure are examined in order to define some of their properties - particularly compressibility and permeability - which it is essential to know when they are placed in an embankment. The author shows that the void ratios of the sheets, even when they are overloaded, remain very great and consequently their permeability is significant. For some of these products the permeability anisotropy is very low. The author then goes on to study the clogging of fabric sheets in contact with a soil (silt or clay) during compacting or static loading tests. He reaches the conclusion that the permeability drop is low, providing the sheets are thick enough, the permeability of the clogged products being approximately similar to sand. the second part is formed by the theoretical study of the consolidation of an embankment drained by fabric sheets. After having applied Terzaghi's unidimensional consolidation theory, the author shows that approaching the phenomenon by this method is not valid since the boundary conditions are not respected. He then suggests a two-dimensional scheme allowing for the dissipation of pressures in the drains; his expression by the method of finite differences has the advantage of permitting computer calculation. Concrete cases are then treated by this method and the variation of different parameters are envisaged: thickness of soil layers, drain thickness, width of the embankment, embankment loading method, soil permeability, drain permeability. This part is of undeniable practical concern since it enables the various embankment construction methods to be compared. Further, a certain number of recommendations go with it (such as the minimal value of the permeability ratio of the drain and the soil, or the minimum thickness of the drain) which will have to guide the users of these products.
Central Laboratory of Bridges & Highways, France75732 Paris, France
- Bourdillon, M
- Publication Date: 1976-6
- Features: Figures;
- Pagination: 40 p.
- Issue Number: 54
- TRT Terms: Consolidation; Drainage; Embankments; Fabrics; Moisture content; Nonwoven textiles; Permeability
- Old TRIS Terms: Consolidation theory
- Subject Areas: Geotechnology; Highways; Hydraulics and Hydrology;
- Accession Number: 00141632
- Record Type: Publication
- Files: TRIS
- Created Date: Feb 1 1977 12:00AM