Numerical Simulation on Creep Properties of Filling Body of Gob-side Entry Retaining

Combined with the mechanical characteristics of underground filling body of gob-side entry retaining, it is concluded that the filling body presents uniaxial compressive state in the underground, the creep characteristics of the filling body was analyzed by Cvisc model in software FLAC^3D numerical simulation, the backfill has experienced transient deformation, steady creep and accelerated creep three stages in the step by step loading process. Among them, the accelerated creep stage of backfill block damages rapidly and the loading strength is basically 70% to 72% of its own strength; then the designed filling strength of 3 MPa and 5 MPa two kinds of schemes are simulated in the coal mine site, it is concluded that the strength of 3 MPa can meet the requirement of gob-side entry retaining without considering the creep characteristic of the filling; however, after the introduction of the time effect, the filling strength of 3 MPa was lost in the filling body after 1.6 years, and the gob-side entry retaining is failure, finally, the filling scheme of 5 MPa is determined. After practice inspection in field, the filling strength is reasonable and the gob-side entry retaining is successful.