Study on Surrounding Rock Structure Evolution Characteristics and Roof Control Techniques of the Retained Roadway Formed by Roof Cutting in Inclined Coal Seams

Figure 13

The simplified mechanical model of the stable zone in the retained roadway. (in the figure, F₁ refers to the support force (kN) of the caved gangues in the goaf on the main roof and F₂ denotes the pressure (kN) on the immediate roof and the gangue-retaining structure by caved gangues in the goaf; and separately represent the side thrust (kN) on rock block B at position C′ and that (kN) on rock block A at position B′; and denote the shear forces (kN) on rock blocks B and A, respectively; σ and x₀ separately refer to the support force (kN) on the coal mass in the plastic zone on the roof and the width (m) of the limit equilibrium zone in coal, respectively; and denote the residual bending moments (kN·m) on the rock beam at positions A′ and B′; and refers to the bending moment (kN·m) caused by the action of the immediate roof on the main roof, respectively.)