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

Figure 12

The simplified mechanical model of the dynamic pressure area in the retained roadway. (in the figure, T_B and T_A denote the side thrust (kN) on rock block B at position C′ and that (kN) on rock block A at position B′, respectively; N_B and N_A represent the shear forces (kN) on rock blocks B and A; σ and x₀ denote the support force (kN) from the coal in the plastic zone on the roof and the width (m) of the limit equilibrium zone in the coal, respectively; M_A and M_B refer to the residual moments (kN·m) on the rock beam at positions A′ and B′; and M₀ denotes the bending moment (kN·m) caused by the action of the immediate roof on the main roof.)