Experimental Evidences of the Effect of Fibres in Reinforcing a Sandy Gravel (original) (raw)
Related papers
Fibre Reinforcement of Sandy Soil
2017
The word sandy soil represents a soil which consists of more amount of sand particles and small amount of clay and silt particles. Sandy soils have fewer loads bearing capacity, less shear strength, less specific surface and they do not have any plasticity. Therefore, the cohesionless soil is mostly settled during earthquake and in heavy rainy season. Owing to such properties of cohesionless soil, it is very difficult to carryout construction work on such soil in a normal way. Several techniques are available for improving the strength of soils for using them as construction materials. Fibre reinforced soil is one of the modern techniques in which fibres of desired type and quantity are added to the soil, mixed uniformly in random directions and then laid in position. . It is one of the most popular techniques used for the improvement of poor soils. Further, soil reinforcement causes significant improvement in tensile strength, shear strength, bearing capacity as well as economy. Th...
E3S Web of Conferences
The effect of the addition of 0.5% of randomly distributed polypropylene fibres in a round grained sand, composed mainly of silica, is presented on laboratory scale. The samples were compacted with two void ratios (0.75 and 0.63), corresponding to values of relative density of 50% and 90% respectively. 24 monotonic triaxial tests were performed, with initial effective mean pressures of 20, 100 and 200 kPa. Half of samples were tested in drained conditions, and the other half in undrained conditions. For the samples subjected to drained conditions, the effect of the fibres was identified at the post-failure stage, by showing sustained increase of strength. The positive effect of fibres could also be observed through the increase of material friction angle. In the samples subjected to undrained tests, the addition of fibres reduced the contractive behaviour, mainly for those more compacted.
The Reinforcement of Sand by Fibres with a Non-Uniform Shape
Slovak Journal of Civil Engineering, 2021
The reinforcement of soil is used to improve its strength and stiffness. The standard method of soil reinforcement is an application of geosynthetics. Soil reinforcement by distributed discrete fibres represents an alternative to those techniques. Currently used fibres have a straight shape, uniform cross-section, and smooth surface, which is not optimal in terms of the fibre-soil interaction. In this study, fibres with a variable shape were utilized. The fibres were fabricated using a fused deposition modelling technology. Firstly, a brief theoretical background is presented. Then, the proposed shapes of the fibres and their manufacturing process are described. The mechanical properties of the soil-fibre composite were investigated through consolidated drained triaxial tests. Well-graded coarse sand and poorly-graded fine sand were used. A higher peak shear strength was observed in the case of fibres with a variable shape. The effect of the variable shape of the fibres on the peak ...
Static and dynamic behavior of soft clay soils stabilized with virgin fibers
1. Background When expansive clay soils are subjected to moisture, they may swell and subsequently their strength decreases. Therefore, presence of such clay soils with possibility of volume change due to environmental effects is known as one of the common problems in geotechnical engineering practice. Nowadays, improvement methods are widely used around the world. Application of these methods in construction improves the geotechnical parameters of the soil, reduces the incurred costs, shortens the construction time, and increases durability of the construction materials. In these methods, the reinforcing or stabilising type of materials are used to strengthen the soil and to improve the engineering characteristics and mechanical properties of the soil, namely shear strength parameters, stiffness, ductility, and load bearing capacity, using scientific principles and new technologies. With advances in soil improvement techniques, there are multiple methods of soil reinforcement and stabilization choices depending on the type of the soil and project condition including mechanical, chemical, physical, biological (growing plant), and electrical techniques. Soil reinforcement technique is considered as a physical method that was first proposed by Vidal et al. (1966) in France. One of the soil reinforcement methods is mixing it with short fibres and filaments. Combination of these reinforcing elements with soil forms a composite material that involvement of reinforcement elements with soil grains improves soil strength and ductility. Gary and al-Rifai were among the first researchers who examined the reinforced soil using triaxial compression tests on fibre reinforced sand, and they showed that the increase in soil strength is proportional to the amount of reinforcing materials. The findings of Ranjan et al (1996). on samples reinforced with fibres using triaxial tests, studies carried out by Wang and Frost using uniaxial and triaxial tests on mechanical behavior of reinforced argillaceous sands, as well as the triaxial direct shear tests conducted by Santoni and Bistro on reinforced sand soils. All studies indicate the fact that the reinforced samples have more ductility than non-reinforced ones, and the shear strength increases by increasing the amount fibres in the soil. Michalowski and Zhao (1996) proposed a measure for breaking of sand reinforced with steel and polyamide fibres based on a comprehensive experimental and theoretical research. According to their study, reinforcement increases the compressive and shear strength of the soil, improves the response of soil mass to dynamic loads, increases dynamic shear moduluse of the soil, reduces liquefaction potential, and increases the soil ductility [1]. Soleimani et al. (2016) investigated the dynamic behavior of the sand containing fibre under triaxial cyclic loading. Their study indicated that adding fibre improves shear strength and the maximum axial strain of the soil [2].
The effect of fiber reinforcement on the behavior of cemented sand
Geotechnical Engineering foundation of the future, 2019
Unconfined compression tests were performed to determine the benefit of using randomly distributed polypropylene fiber reinforcement mixed with Portland cement on the engineering behavior of sandy soils. Fiber length was 19 mm and the content of fiber was 0%, 0.1%, 0.3% and 0.5% by the dry weight of soil while the content of cement was 3%, 5% and 7% by the dry weight of soil. The samples were prepared at optimum water content and cured for 7 and 28 days in a moisture-curing tank. The results show that the addition of fiber reinforcement to the cemented soil results in increasing the unconfined compressive strength and axial strain at failure and it changed the behavior of the cemented soil from brittle behavior to a more ductile behavior. RÉSUMÉ: Des essais de compression sans confinement ont été effectués pour déterminer l'avantage d'utiliser un renforcement de fibres de polypropylène à répartition aléatoire mélangé à du ciment Portland sur le comportement technique des sols sableux. La longueur des fibres était de 19 mm et la teneur en fibres était de 0 %, 0,1 %, 0,3 % et 0,5 % en poids sec du sol tandis que la teneur en ciment était de 3 %, 5 % et 7 % en poids sec du sol. Les échantillons ont été préparés à une teneur en eau optimale et séchés pendant 7 et 28 jours dans un réservoir de durcissement à l'humidité. Les résultats montrent que l'ajout d'un renforcement de fibres au sol cimenté augmente la résistance à la compression non confinée et la déformation axiale à la rupture et modifie le comportement du sol cimenté du comportement fragile à un comportement plus ductile.