• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.5
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• pp.93-98
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• 1999

The results of an experimental investigation on the characteristics of compaction and compressive strength of polypropylene fiber reinforced soil are presented in this paper. This study has been performed to obtain the physical properties of PFRS(polypropylene fiber reinforced soil) such as strain-stress relationships, OMC(optimum moisture contents) and ${\gamma}$dmax (maximum dry unit weight), with four different contents (i.e., 0.1%, 0.3%, 0.5% and 1.0% weights ) of mono-filament and fibrillated polypropylene fibers. From the compaction test results, it is found that OMC increased with the contents ratio of fiber, but ${\gamma}$dmax decreased. It means that the improvement of the workability and the reduction of the weight of embankment structures by the asddtion of the polypropylene fiber. And, from the compression test results, it is found that the additon of the polypropylene fiber remarkably improved the compressive strength of PFRS. And it was observed in the viewpoint of strength that the fibrillated polypropylene fiber reinforced soil is more effective than the mono-filament polypropylene fiber reinforced soil.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.3
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• pp.59-65
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• 1999

This study has been performed to confirm the three dimensional effect of the crack reduction and the restrained effect of crack growth for the synthetic fiber reinforced soil. Two types of polyrpropylene fiber and low plastic clay(CL) were used for the test. And the test variable were fiber length and so on. The results of the study were summarized as follows ; 1) The mixing of synthetic fiber was effective in reducing crack growth due to adhesion between soil partlcles and synthetic fiber.l Especially initlal crack was delayed, as compared with the pure soil, for about 1 day in case of mono filament synthetic fiber and for about 1 or 2 days in case of fibrillated syntetic fiber. 2) As the content and length of synthetic fiber were increased , the effect of crack reduction was increased. It was found that 0.5% fibrillated synthetic fiber with 40mm length reinforced soil had about 3 times more effective than natural soils. 3) In case of the same fiber content and fiber length, the fibrillated synthetic fiber has nmore effective than the mono filament synthetic fiber for crack reduction.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.503-513
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• 2019

In the present, the liquefaction potential of fiber-reinforced sandy soils was investigated through the energy-based approach by conducting a series of strain-controlled cyclic simple shear tests. In the tests, the effects of the fiber properties, such as the fiber content, fiber length, relative density and effective stress, and the test parameters on sandy soil improvement were investigated. The results indicated that the fiber inclusion yields to higher cumulative liquefaction energy values compared to the unreinforced (plain) ground by increasing the number of cycles and shear strength needed for the liquefaction of the soil. This result reveals that the fiber inclusion increases the resistance of the soil to liquefaction. However, the increase in the fiber content was determined to be more effective on the test results compared to the fiber length. Furthermore, the increase in the relative density of the soil increases the efficiency of the fibers on soil strengthening.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.594-598
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• 1999

To analyze the characteristics of unconfined compressive strength of reinforced soil bricks made of clayey and sandy mixed with cement, lime, staple fiber and their combinatioin , a series of unified comparessive tests was performed. The resutls are summarized as follows ; 1) Reinforcing effect of reinforced clayed soil and that of soil brick of sandy soil mixed with cement and staple fiber is 8 times greater than no reinforced sandy sol. Therefore, the reinforcing effect seems to be greater in sandy soil than in clayey soil . 2) Lime shows a negative reinforcing effect in clayed soil but a little reinforcing effect in sandy soil. 3) It is appeared that strain at failure of soil brick reinforced with staple fiber is greater than that of unreinforced brick regrardless of soil's type.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.596-600
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• 2002

To analyze the settlement characteristics of short-fiber reinforced soil(SFRS), which will be used as a new backfill material of reinforced retaining wall, under simulated railroad loading, a series of tests with loading condition of 5 Hz frequency and 500,000 cycles were performed. The materials used for tests are soils with SM or ML type, and polypropylene short-fibers with mono-filament(PPM) or fibrillated type(PPF). From the tests, average plastic settlement is low at PPF38(0.3%)(abbreviation of PPF with 38mm length and mixing ratio 0.3%), PPF38(0.5%), PPM60(0.2%) for SFRS using SM soil and at PPF38(0.3%), PPF60(0.2%) for SFRS using ML soil. Elastic settlement is low at PPM60(0.2%) for SFRS using SM soil and at PPM60(0.5%) for SFRS using ML soil.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.6
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• pp.90-97
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• 2000

In this study, the variation of unit weight and unconfined compressive strength were investigated, calcium carbonate, quicklime, portland cement, 19mm length monofilaments and fibrillated fiber were used as reinforcement materials. And calcium chloride was added to cement and calcium carbonate reinforced soil mixture in order to accelerate setting and hardening speed. It appears that unit weight is highest in calcium carbonate reinforced soil mixture with mixing rate of 9%. According to increasing the amount of fiber in soil mixture, the unit weight decreased. It shows that the more the amount of monofilament fiber is added in soil mixture, the higher the compressive strength is, but the compressive strength is decreased in fibrillated fibrillated fiber added soil mixture with more than 1.0% of mixing rate.

• Geomechanics and Engineering
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• v.39 no.2
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• pp.143-155
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• 2024

Traffic-induced cyclic loading leads to the rotation of principal stresses within pavement foundations, challenging accurate simulation with conventional triaxial testing equipment. To investigate the deformation characteristics of fiber-reinforced soil under traffic loads and to develop a fractional-order model to describe these deformations. A series of hollow cylinder torsional shear tests were conducted using the GDS-SSHCA apparatus. The effects of fiber content, load frequency, cyclic deviatoric stress amplitude, and cyclic shear stress amplitude on soil deformation were analyzed. The results revealed that fiber content up to 3% enhances soil resistance to deformation, while higher fiber content reduces it. Axial cumulative plastic deformation decreases with higher load frequencies and increases with higher cyclic stresses. The study also found that principal stress rotation exacerbates soil deformation. A fractional integral model based on the Riemann-Liouville operator was developed to describe the axial cumulative plastic strain, with its validity confirmed by supplementary tests. This model provides a scientific basis for understanding foundation deformation under traffic loading and contributes to the development of dynamic constitutive soil models.

• Geotechnical Engineering
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• v.11 no.2
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• pp.107-120
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• 1995

The purpose of this study is to investigate the effects of fiber on engineering properties of Fiber-Reinforced Soil. Engineering properties of soil reinforced with discrete randomly oriented inclusion depend on soil density, particle size, grading, fiber length, tensile strength and stiffness of fiber, mixing ration of fiber, confining stress, etc.. in this paper, the influence of fiber shape, fiber length, fiber diameter, fiber content, cement content and curing duration on engineering characteristics(compaction, shear & permeability) were evaluated for typical soils produced from construction works through uniaxial compression tests and triaxial compression tests. From the experimental results, it was also investigated if there is an optimal range of fiber lengths and fiber contents for the tested soils and tested mono-filament fibers.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.461-466
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• 1998

The purpose of this study was to evaluate the properties of unconfined compressive strength(UCS) of dry soil which was reinforced with short polypropylene fiber(SPPF). And the results were summarized as follows: 1. As water content was increased, unconfined compressive strength and strain of dry soil with no fiber added were decreased 2. As mixing ratio of fiber was increased, unconfined compressive strength and strain at failure of dry soil reinforced with SPPF were increased. 3. When mixing ratio was larger than 0.5％, unconfined compressive strength was gradually increased. 4. The longer fiber was, the larger post peak strength was obtained and the larger strain was reached.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.6
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• pp.59-70
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• 2005

A series of resonant column test was performed to investigate the dynamic deformation characteristics of silty sand soils mixed with polypropylene fibrillated type fiber. Results show that optimum mixing ratios were $0.2\%$ for 19mm of cut fiber for shear modulus and $0.1\%$ for 60mm cut fiber fur damping ratio. As shear strain was increased, normalized values of shear modulus (G(Reinforced)/ G(Unreinforced)) of fiber reinforced soil were increased up to $10^{-3}\%\~10^{-1}\%$ ranges. However, normalized damping ratio (D(Reinforced/D(Unreinforced)) was diminished with an increase in strain beyond $10^{-3}\%\~10^{-1}\%$ for the damping capacity of soils mixed with fiber. Normalized shear modulus $(G/G_{max})$ obtained from the test was plotted in the chart suggested by Seed and Idriss. The shear modulus of silty sand was located between sand and gravel curves.