Studies on the potential of coir reinforced structures.

Geotextiles made of natural fibres are increasin gly finding a pl ace in erosion control, but not for soil reinforcement application, in spite of the fact that strong fibres like coir which have a very hi gh lignin content can be effectively made use of provided they are given suitable treatment. This paper deals with potentialities of coir products like coir ropes, coir felt and grids for improving weak subsoil. The effectiveness of coir n.felt on clay beds were examined using CBR type penetration tests on a kaolinite clay bed at fast and slow rates of strain with a view to comparing them with sand blankets used for acceleratin g consolidation. The needled felt was also strengthened by nylon nettin g and coir grid s. Limited cyclic wetting and drying tests performed on these products showed th at the strength is not significantly reduced by these tests. It is concluded that needled felt is a good seating layer to economise on sand blankets for clay formation on which embankments can be constructed at a fast rate as there is little possibility of undrained failure. Light bituseal and cement-PYA coating help to improve both the resistance and durability of the coir composites.