Please use this identifier to cite or link to this item: http://localhost:8081/xmlui/handle/123456789/5666
Authors: Jain, Ajay Kumar
Issue Date: 1990
Abstract: India is a large country with contrasting terrain, weather and environmental conditions and a large area is covered by weak soils like black cotton soils, peats, clays etc. These soils are not structurally sound to bear the traffic load. It is therefore, often required' to stabilise and reinforce the soil by some method. Different types of materials are being increasingly employed in highway engineering to facilitate construction, ensure better performance and reduce maintenance. Few attempts have been made to use metallic and other materials. But they are not found cost and performance effective. Based on comprehensive experimental and research programmeS undertaken in developed countries non-metallic materials may be suitable for reinforcement. Geotextilesare the new development in the field of reinforcing materials,. These materials are thin, bi-dimensional, flexible anti-corrosive, non-biodegra-non-toxic and ultravoilet stabilized for long life. In the present study, various laboratory experiments like CBR tests, triaxial tests and direct shear tests were conducted on unreinforced and reinforced subgrade soils to see the reinforcing effect imparted by geotextiles. Two types of soils were used and soaked and unsoaked CBR was determined by placing the geotextile at different heights. It was observed that the CBR of both soils improves considerably when geotextile is placed in the sample, which ultimately leads to a thinner pavement section. CBR value of soil A (sandy) increases by 135% and that of soil B (clayey) increases by 97% when these are reinforced by geotextile. Maximum increment in CBR is achieved when geotextile is placed near the surface of sample. Similarly triaxial load tests were conducted on soil samples by placing the geotextile and different heights and test were conducted at different confining pressures. It was observed that confining pressure and position of geotextile has effect on deviator stress and 'E' value. The value of peak deviator stress increases by 49.2%' and 31.0% in soil A and son. B ( iv) respectively in reinforced samples. Strength of soil sample increases with increase in the number of reinforcing layers. Modulus of elasticity of reinforced subgrade soil also improves in comparison to unreinforced soil samples. Results of direct shear tests on reinforced and unreinforced soil revealed that angle of internal friction increases from 12.0° to 14.5° and 5.5° to 7.5° in soil A and B respectively in single layer reinforcement and from 12.0° to 16.0°'and 5.5° to 8.5° in soil A and B respectively in double layer reinforcement. Similarly cohesion value is increased by 40% and 66% in single and double layer reinforcement respectively in soil A. These values are 48% and 58% respectively for soil B. The study on repeated plate load tests on unreinforced and reinforced pavement slabs reveals that introduction of geotextile layer at subgrade- base course interface reduces the subgrade and surface deformation by 60% and 20% for 30,000 load repetitions respectively. Therefore life of, the pavement will be enhanced
Other Identifiers: M.Tech
Research Supervisor/ Guide: Chandra, Satish
Mehndiratta, H. C.
metadata.dc.type: M.Tech Dessertation
Appears in Collections:MASTERS' DISSERTATIONS (Civil Engg)

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