Abstract: In view of the easy abrasion of backfilling pipelines, an investigation is made of the filling drill-holes in Jinchuan mine area. It is found that the abrasion caused by the impact of pulp in free falling is the main wear mode of filling pipeline. The physical and mechanical model for slurry flow is established and the wear mechanism of filling pipeline discussed from the viewpoints of moment and energy. The study indicates that the longer the distance of free falling, the greater the speed for the slurry to arrive at the interface between air and slurry and the more serious the impact abrasion on local pipe wall. A concept of energy consumption of unit area of pipe wall is proposed and it is concluded that the higher the energy per unit area of pipe wall, the faster the pipe wall abrasion.

Key words: Backfilling pipeline, abrasion form, Slurry flow state, Mechanism study