Abstract：The influence of staggered distance on the failure of floor strata in double-longwall mining on the confined aquifer is local and temporary. After longwall mining having reached a certain scale，the failure depth in floor strata depends on macroscopic parameters of mining technology and geological conditions. The current and ultimate failure depth of the floor strata does not change due to the magnitude of mining staggered distance (5～30 m). Based on the mining geological conditions of a practical double longwall mining panel，a rational staggered distance of double-longwall faces is proposed to be within 10 m，by means of observing the changes of in-situ abutment pressure and 3D coupled numerical modeling of fracture in floor strata.
