The objective of this study was to examine the influence of discrete and randomly distributed fibres on heave of an expansive soil. One-dimensional swell tests were conducted on a remoulded expansive soil with and without fibres. In this study, fibre content was varied as 0.25 and 0.5% and fibre length as 30, 60 and 90 mm. A twin semi-circular-shaped fabricated mould with a front Perspex sheet was developed for testing. Digital imaging technique was used to observe heave of the soil in both unreinforced and fibre-reinforced conditions. Displacement profiles obtained from image analysis were used for interpreting swell or upward movement profiles of the specimens. Heave observed in the digital image analysis was compared with that obtained from dial gauge readings. Reduction in heave was directly proportional to fibre content and fibre length. Reduction in heave was the maximum at low aspect ratios at both fibre contents of 0.25 and 0.5%. Test results revealed that fibre length is a key factor that influences the reinforcing effect of fibre. Discrete and randomly distributed fibres were found efficacious in reducing heave. © 2009 Thomas Telford Ltd.

B.V.S. viswanadham

B.R. Phanikumar

Viswanadham B.V.S

R.V. Mukherjee

Phanikumar B.R

Mukherjee R.V.

digital image analysis

Expansive soils

Fibre reinforcement

Geosynthetics

Polypropylene fibre

Soil stabilization

swelling

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Geosynthetics International

Expansive soils are considered to be highly problematic because of their capacity to significant volume change. They swell during the rainy season as they absorb water and shrink when water evaporates from them during the summer season. Because of this dual swell-shrink behaviour, an expansive soil causes severe distress to many civil engineering structures. Several mitigating techniques are adopted to counteract the problems posed by the expansive soils, either by modifying the properties of the soil by adopting stabilization techniques using lime, cement, fly ash, calcium chloride etc. or by adopting special foundation technique such as construction of belled piers, under-reamed piles, etc. In recent years polymeric fibres have also been used to stabilize the soil as well as to improve the strength of the expansive soils. Hence in the present study lime and fibres have been used in different proportions to study the swelling and shrinkage behavior of expansive soils. Swell tests were performed by varying the fibre content and lime with expansive soils. Tests were also conducted by blending fibres and lime together with expansive soils. In a similar way, shrinkage tests were also performed for the various proportions. The test result show that swelling tends to decrease slightly with an increase in the fibre content, whereas shrinkage tends to decrease significantly upon addition of fibres. Both swelling and shrinkage tends to decrease significantly with increasing lime content. The optimum content of fibre was found to be 2%. So the expansive soil specimens blended with 2% fibres and with varying lime content was tested. It is found that blending 2% fibres and 15% lime together in expansive soils is considered to be more effective in controlling the swelling and shrinkage behaviour.

Sustainable Civil Infrastructures Advances in Reinforced Soil Structures

Swelling and Shrinkage Behaviour of Expansive Soil Blended with Lime and Fibres

Fulltext

Soils and Foundations

Swell-consolidation characteristics of fibre-reinforced expansive soils

The objective of this paper is, through laboratory experiments, to examine the effect of discrete and randomly distributed fibers on the piping behavior of soil. A silty sand type of soil having 20% fines was selected in the present study. Two types of geofiber, polypropylene and polyester, were used. In this work, various experiments were carried out to determine the influence of geofibers with various dosages and lengths on the seepage velocity and piping resistance of soil. A fiber dosage up to 0.15% only was adopted. It was observed that geofibers increased the critical hydraulic gradient and caused a significant delay in piping phenomena. The observed piping behavior of soil with and without geofibers was verified by conducting constant-load tests in the laboratory. Based on the analysis and interpretation of these experiments, the mechanism of discrete fiber reinforcement in restraining piping of soil is explained. © 2010 Thomas Telford Ltd.

Experiments on the piping behavior of geofiber-reinforced soil

This paper reports the results of laboratory study performed on expansive soil reinforced with geofibers and demonstrates that discrete and randomly distributed geofibers are useful in restraining the swelling tendency of expansive soils. Swelling characteristics of remoulded expansive soil specimens reinforced with varying fiber content (f = 0.25% and 0.50%) and aspect ratio (l/b = 15, 30 and 45) were studied. One-dimensional swell-consolidation tests were conducted on oedometer specimens. Reduction in heave and swelling pressure was the maximum at low aspect ratios at both the fiber contents of 0.25% and 0.50%. Finally, the mechanism by which discrete and randomly distributed fibers restrain swelling of expansive soil is explained with the help of soil-fiber interaction. © 2008 Elsevier Ltd. All rights reserved.

Geotextiles and Geomembranes

Swelling behaviour of a geofiber-reinforced expansive soil

Foundation Engineering for Expansive Soils

Soil Suction

Experimental investigation of the strength properties of sand–clay mixtures reinforced with randomly distributed discrete polypropylene fibers

Geotechnical and Geological Engineering

Cyclic Swell–Shrink Behaviour of a Compacted Expansive Soil

The objective of this paper is to study the deformation behavior of moist-compacted soil liners with and without inclusion of discrete and randomly distributed fibers for waste containment systems at the onset of nonuniform settlements in a geotechnical centrifuge. First, scaling considerations pertaining to simulation of discretely mixed fibers in a centrifuge are presented. A series of centrifuge tests were carried out by varying aspect ratio and dosage of fibers in a soil liner of 1.2 m thick and compacted at its standard Proctor compaction. Controlled in-flight simulation of nonuniform settlements in a centrifuge was carried out using a trap-door arrangement at 40 g. It was observed that the aspect ratio and fiber content has a significant affect in restraining cracks for a randomly reinforced soil liner at the onset of nonuniform settlements. In addition to centrifuge test results, flexural behavior of soil beams with and without discrete and randomly distributed fibers was evaluated in the laboratory to bring out significance of fiber content and aspect ratio. The analysis and interpretation of test results indicate the significant potential for fiber reinforcement to decrease and to retard soil crack potential in a randomly reinforced soil liner while retaining its hydraulic performance. © 2009 ASCE.

Practice Periodical of Hazardous, Toxic, and Radioactive Waste Management

Centrifuge testing of fiber-reinforced soil liners for waste containment systems

Effect of polypropylene tape fibre reinforcement on swelling behaviour of an expansive soil

Journal	Geosynthetics International
ISSN	10726349
Open Access	No