Experimental Study on Static Mechanical Properties of Cemented Tailings Backfill with Hybrid Fiber.

With the aid of an electronic universal testing machine and a scanning electron microscope, uniaxial compression tests and microscopic examinations of cemented tailings backfill with mixed fibers were carried out in order to investigate the impact of mixing steel fiber (SF) and polypropylene fiber (PF) on the static mechanical properties and failure mode. The findings demonstrate that; the inclusion of hybrid fiber has a substantial impact on the failure mode of the backfill; the CTB is mostly damaged by single bevel shear, displaying an evident brittle failure;the SP-FRB is primarily damaged by relatively minor secondary cracks due to the bridging and crack-resisting action of internal fibers; and the specimen is fractured as a whole,demonstrating an obvious ductile deformation; The addition of hybrid fiber can increase the filler s uniaxial compressive strength,but there is a maximum amount that should be used. The stress-strain curves of both CTB and SP-FRB contain four stages: pore compaction, linear elastic deformation, plastic yield,and post-failure. The results of the microscopic tests indicate that the initial pore size and number inside the filler are significant factors in its failure. Steel fiber and polypropylene fiber can both maintain high integrity inside the filler and prevent crack expansion through adhesion with the matrix and their own fatigue fracture, respectively. [ABSTRACT FROM AUTHOR]