Application of laminated beam theory in stress analysis of composite roof

In order to analyze the stability of composite roof and the effect of rockbolt combination, the laminated beam theory was applied to the composite roof, and the non-common curvature, common curvature and integral beam models of laminated beam were compared. The distribution law of bending moment, the magnitude and ratio of tensile stress and their influencing factors of composite roof beams under different models were analyzed, and the applicable conditions of each model were obtained. The research shows that the stability of composite roof calculated by the three models is very different, and when the height-span ratio is greater than 1/3, the composite roof laminated beam can be approximated as a common curvature model; when the height-span ratio is less than 1/3, the laminated beam should be analyzed according to the non-common curvature model; the integral beam model can be used when the interlayer bonding force is not destroyed. The analysis shows that active and passive reinforcement mechanism of composite roof rockbolt is mainly to prevent the transformation of composite roof from integral beam to common curvature laminated beam and non-common curvature laminated beam, realize the transformation from non-common curvature laminated beam to integral beam, so as to enhance the bending capacity of composite roof and roadway stability.