Shear response and distribution optimization of polypropylene fiber-reinforced tailings under a three-dimensional model of reinforcement and soil separation

To investigate the effects of polypropylene fibers on the shear properties of reinforced tailings, in this paper, a new three-dimensional finite element model featuring discrete reinforcement and soil elements is presented. This model is based on data from direct shear tests of tailings reinforced with polypropylene fibers, secondary development of ABAQUS preprocessing via the Python language, random distribution of fibers in the tailings matrix, and the influence of different fiber parameters on the numerical simulation of reinforced tailings. The test results show that the addition of polypropylene fibers can significantly improve the shear strength of tailings, and when the fiber content is less than or equal to 0.3%, the experimental value and the simulated value are in good agreement. When the fiber content exceeds 0.3%, the experimental values differ greatly from the simulated values. The maximum deviation between the test value and the simulated value of the shear strength of reinforced tailings with different fiber lengths is 15%, and the fiber length corresponding to the maximum deviation is 3 mm. Except for the 3 mm short fiber dimension, the deviation between the test value and simulation value of the reinforced tailings with other fiber lengths is less than 5% Under different distribution states of the polypropylene fibers, the stress on the fiber is the greatest when the fiber is randomly distributed, indicating that the fiber can bear more stress under a random distribution state. The stress on the fiber exhibits relatively small differences when the fiber distribution angle is 30°, 45° or 90°, and the stress on the fiber reaches its minimum when the fiber distribution angle is 0°. This three-dimensional finite element model can provide a reliable basis and technical support for calculating the reinforcement and soil of various fibers and matrices separately by changing the material parameters,The research results provide a reference scheme for roadbed reinforcement engineering.