Fig. 1
From: Study on the fracture characteristics of overlying rock strata under different mining face widths
Mechanical model of overlying rock strata before fracture. q is the lateral uniform load applied to semi-infinite beam A, N’ and Q’ are respectively the x-axis force and shear force caused by the already fractured and rotationally stable beam B, Q0, M0 and N0 are respectively the shear force, bending moment and x-axial force in the cross-section at x = 0 m, F is the support resistance caused by hydraulic support, l is the distance between the support resistance point and coal rib, L is the length of cantilever beam, k is the modulus of subgrade reaction of foundation strata.
