Abstract: Backfilling hydraulic support is key equipment which not only has the function of supplying the space for coal mining as traditional hydraulic support, but also has the special function of supplying the space for solid materials backfilling. The concept of backfilling characteristics has been approved because of the special function, meanwhile, the basic implication of backfilling characteristics has also been analyzed through the following six aspects: supporting intensity, supporting intensity of rear roof canopy, movement feature, compacting force, roof gap and the geological conditions adjustment feature. The backfilling characteristics is mainly influenced by support structure, geological conditions, backfilling technique, during which the support structure plays an important role; besides, thickness, roof and floor conditions, dip angle and depth of coal seam also have a huge influence on the effects of backfilling characteristics; and the backfilling technique will influence the backfilling performance by changing the value of roof gap and compacting force and the adjustment feature to different geological conditions. The effect of backfilling characteristics can be improved through working face layout optimization, structure design optimization, backfilling technique optimization and real time online monitoring during engineering practice. The research result has been proved by the using of ZZC10000/20/40 backfilling hydraulic support with six props and four-bar linkage in Jining No.3 Coal Mine.

Key words: backfilling hydraulic support, backfilling characteristics, influencing factors, compacting force, movement feature