关键词: 宏观结构, 结构变化, 微观结构, 纤维掺量, 含水率

Abstract: Experimental study was carried out to investigate the influence of polypropylene fibre on the shear behavior， compressive behavior and microstructural properties of polypropylene fiber-reinforced iron tailings. The shear behavior was determined by the shear resistance， and the compressive behavior was determined by the unconfined compressive strength. The structural changes of the fiber-reinforced tailing sand were evaluated by macrostructural failure analysis and microstructural test with SEM analysis. The tests was designed to research the influenence of fiber contents and moisture contents on the tailings specimens. The results showed that the fiber is an important factor to improve the shear strength and unconfined compressive strength， and the reinforcement effect mainly depends on the friction and bonding between the fiber interface and the sand interface. The best fiber contents is 0.3%， and the best moisture content is 12% in the shear tests and unconfined test. In addition， the macroscopic structural failure analysis and SEM microstructural tests showed that the action of polypropylene fiber is mainly to bridge the crack and counteract the external force through the friction force at the fiber interface and the sand interface to achieve the purpose of increasing the strength.

Key words: macrostructure, structural change, microstructure, fiber contents, moisture contents