Mechanism And Control Of Floor Heave In Three Soft Coal Seam Drifting Along Goaf

The mechanism and control of coal seam with soft coal, roof and floor roadway floor heave is a difficult problem in mining subject. Above all, The paper points out that the bottom strata breach of roadway is elastic and plastic deformation during the period of tunneling through analyzing stability of overlying strata and distribution of lateral abutment pressure before mining. Building the mechanical model of bottom strata and disposing the principle of gob side entry driving floor-heave, through analyzing the law of motion of cover rock and distribution of abutment pressure on the side of entity coal during the period of mining; And then, Adequacy analyzing the physical and mechanic property of three soft coal strata and discussing the floor-heave mechanism of three soft coal strata, according to extensiveness rock mass as research subjects and binding mechanical model of bottom strata; Through the theoretic computation or experimental formulas, the measure of floor heave arise from the factors as the elastic and plastic deformation, the rock dilatancy and rock creep are estimated; One mechanical model accounting for the structure expansion of rock peak-residual deformation is put forward; thereby the mechanism of serious floor heave arise from rock peak-residual deformation and rock creep. The paper ascertains the rational coal column breadth and discussing the influence of law of motion of roof strata and abutment pressure for floor heave. The approaches and proper method of controlling floor heave are brought forward, The efficiency of the supporting method of whole section bolt and cable is established through the numerical calculation of reinforcement for roof, both sides and basic angle, and indicates the key factors lie in the reinforcement of both sides angles and enhancement of self-bearing ability of coal pillar; the supporting project has successfully been put into practice , vast economic profit and technological effect has been achieved , as well as a good method to control for the floor heave of similar roadway has been given.