Abstract: For the backfill horizontal movement of gob-side entry retaining in deep mine, the characteristics of horizontal movement of backfill in deep mine with compound roof are analyzed; the horizontal pressure of backfill suffered from gob caving gangue based on elastic foundation beam theory and friction force between backfill and roof(floor) are calculated; based on the condition of 1115(1) working face tail entry in Guqiao mine of Huainan mining area which is typical condition of gob-side entry retaining with compound roof in deep mine; and then the mechanical model of backfill is established; the backfill horizontal movement expression of gob-side entry retaining with compound roof in deep mine is obtained. The results show that: (1) Due to the development of the compound roof fissure, it has a good flow ability after the collapse; it is easy to produce horizontal squeezing force on the filling during the rotation of the key block, and the given deformation of key block can be absorbed by compound roof which leads to the backfill is not easy to insert the bottom; therefore, the backfill is more prone to shift to roadway under the condition of gob-side entry retaining with compound roof in deep mine. (2) Theoretical calculation displacement of backfill is 0.536 m; the field measured displacement is 0.55 m; the results verify the correction of researches. According to the characteristics of backfill horizontal movement, the supporting scheme that increasing the friction factor by using shear bolts between backfill and roof(bottom) and setting isolation piles near the backfill in gob to isolate the backfill and gangue are proposed.

Key words: deep mine, compound roof, gob-side entry retaining, backfill, horizontal movement