BEHAVIOUR OF RANDOMLY DISTRIBUTED FIBRE REINFORCED CLAY

Abstract

To utilize effectively, even poorest of the poor soils for civil engineering projects, efforts of geotechnical engineers are directed to develop technically viable and economically feasible methods to improve the mechanical properties of soil to suit the requirements of engineering structures. Various soil improvement methods have been developed to improve soil properties. Among recent development, a relatively new soil strengthening technique is mixing of randomly distributed discrete fibres to the soil, termed as "ply soil". This technique is considered as an effective ground improvement technique because of its cost effectiveness, easy adaptability and reproducibility. Randomly distributed fibre reinforced soil has significant effect on mechanical properties of soil. However determination of mechanical properties of RDFS (ply soil) is perhaps one of the difficult problems, faced by geotechnical engineers. The main difficulty is due to the, number of variable parameters related to fibre and soil type, which influence the strength properties as well as behaviour of RDFS. In the present work, an attempt has been made that out of number of variable parameters; study the influence of fibre length as well as percentage of fibre content on the strength properties and behaviour of RDFS. Different type of tests viz, standard proctor tests, unconfined compression tests, consolidation tests, triaxial tests, and C.B.R. tests have been conducted on soil with different fibre length (6mm, 10mm, 20mm) and fibre content (0.1%, 0.2%, 0.3%) as percentage of dry weight of soil. The intermediate compressible clay (Cl) has been used as soil material while polypropylene type fibres were used in experimental work. Triaxial tests have been carried out in consolidated undrained condition while C.B.R. tests have been carried out in soaked condition. All tests were carried out at maximum dry unit weight and optimum moisture content of soil. The results show significant increase in strength properties with increase in length as well as fibre content upto specific limit.