Behavior of discrete fiber-reinforced sandy soil in large-scale simple shear tests

Abstract

This study presents results from a series of large-scale simple shear tests performed on sandy soil reinforced with randomly distributed fibers. The soil was mixed with polypropylene, glass and basalt fiber, respectively, with fiber content varying from 0% to 2% and sheared under a normal stress ranging from 100 kPa to 300 kPa. The effects of fiber type, content and normal stress on shear strength and the dilatancy behavior were examined. The friction state theory was employed to interpret the influence of fiber reinforcement on the dilatancy behavior. The results indicate that the additions of polypropylene and basalt fibers are beneficial to enhancing ultimate shear strength, whereas the glass fiber makes little contribution. It is shown that the fiber inclusion hinders the close packing and interlocking of soil particles and hence produces relatively looser soil fabric in the as-compacted state, leading to increased volume contraction accompanied by a negligible improvement or even reduction in shearing stiffness over a small to moderate strain range. The most obvious increase in shear strength generally occurs at a shear strain exceeding 10%, where the fibers and particles are in tight contact with each other, allowing full interface interaction and the mobilization of fiber tensile strength.

Numerical Investigation of Mechanical Performance and Micro-Structure Failure of Polymer-Fiber Reinforced Sand

“…Jairaj et al [17] used naturally grown sisal fibers to improve sandy soil and found that the addition of the fibers significantly improved the mechanical strength of the soil, with an optimal sisal fiber content of 2%. Xu et al [18] conducted direct shear tests on polypropylene-, glass-, and basalt-fiber-reinforced sand using large-scale direct shear tests to compare and study the shear strength and shear expansion phenomenon of reinforced sand under different fiber-content conditions. Reddy et al [19] conducted California bearing ratio (CBR) tests on black cotton soil reinforced with different amounts of sisal fibers, and the results showed that the CBR value of the reinforced soil was the highest when the amount of sisal fiber was 0.75%.…”

Effects of Freeze–Thaw Cycles on Strength and Wave Velocity of Lime-Stabilized Basalt Fiber-Reinforced Loess

“…Basalt fiber has unique characteristics, such as good ductility, high strength, and high-temperature resistance, and appears to have less environmental impact than glass fiber and petroleum chemical fiber [ 22 , 23 ]. Xu, et al [ 24 ] and Jiang, et al [ 25 ] found that basalt fibers were significantly more effective in reinforcing sandy soils than glass fibers and polyvinyl alcohol fiber. Gao, et al [ 26 ] found that basalt fiber’s inclusion enhanced the cohesive strength of clay, and its reinforcement effect increased with the increasing fiber content.…”

Interface Shear Behavior of Geogrid-Reinforced Calcareous Sand Under Large-Scale Monotonic Direct Shear

“…Reinforced soil technology has been widely used in many geotechnical engineering projects for its advantages of convenient construction and effective improvement of soil strength and structural stability [16][17][18][19][20][21]. Reinforced-soil interface parameters are the key technical indicators of reinforced soil engineering structural design, and the interaction characteristics of reinforced-soil interface are the core issues in the study of reinforcement mechanism [22][23][24][25][26]. Pullout test and direct shear test are the two most effective test methods to study the interaction mechanism of reinforced soil interface [23,27,28].…”