Abstract
Resource utilization of iron tailings powder is an effective measure to reduce the dam-break risk of an iron tailings reservoir. Adding polypropylene fiber to iron tailings powder can improve its shear performance. Direct shear tests were carried out on reinforced iron tailings powder with polypropylene fiber with dosages of 0%, 0.25%, 0.5%, 0.75%, and 1%, respectively. The normal stresses during the tests were 100, 200, 300, and 400 kPa, respectively. The test results show that with the increase of polypropylene fiber dosage, the cohesive force of iron tailings powder firstly increases and then decreases gradually, and the internal friction angle firstly decreases and then increases. The back propagation (BP)neural network was used to fit the shear force (F) and shear displacement (s) of the test to obtain the F-s function relationship that satisfies the accuracy. Based on the energy dissipation theory, the direct shear energy dissipation of polypropylene-fiber-reinforced iron tailings powder was calculated. The mathematical model of energy dissipation of fiber interfacial failure was derived by the fiber distribution model. The interfacial strength parameters of polypropylene fiber were calculated based on the direct shear test data and the mathematical model of fiber interfacial energy dissipation. The test results show that the addition of polypropylene fiber from the perspective of energy dissipation can improve the shear properties of iron tailings powder.
Highlights
Iron tailings are one of the products of iron ore sorting operations
Taking the effects of fiber dosage, fiber length, relative compactness, and confining pressure into consideration, Chegenizadeh et al carried out a series of cyclic triaxial tests on unreinforced and reinforced specimens to study the effect of bulk continuous fibers (BCF) on the liquefaction resistance of low plasticity silt [17]
When the dosage was increased from 0.25% to 1%, the it is difficult to analyze the reinforcement effect of polypropylene fiber on iron tailings powder using cohesive force gradually decreased from 31.9 to 9 kPa, which was lower than that of iron tailings the variation law of cohesive force and internal friction angle
Summary
Iron tailings are one of the products of iron ore sorting operations. The stacking of tailings affects the surrounding environment, and seriously threatens the lives and property security of the people in the lower reaches of the reservoir area. Taking the effects of fiber dosage, fiber length, relative compactness, and confining pressure into consideration, Chegenizadeh et al carried out a series of cyclic triaxial tests on unreinforced and reinforced specimens to study the effect of bulk continuous fibers (BCF) on the liquefaction resistance of low plasticity silt [17] It can be seen from the above research results that fiber materials are widely used in sand, clay, expansive soil, and silt, which can improve the mechanical properties of the soil to some extent. Based on the energy dissipation theory, and referring to the research results of fiber-reinforced soil, the shear properties and interfacial strength parameters of fiber-reinforced iron tailings powder are studied. The shear performance mechanism of polypropylene-fiber-reinforced iron tailings powder was analyzed to provide reference for the resource utilization of iron tailings powder
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