Cooperative supporting effect of intermediate bridge and inner dump on slope in adjacent open-pit mining area

Abstract To solve the problem of dynamic demolition of intermediate bridges, study on the calculation method of slope stability under the synergistic support effect of the intermediate bridge and the inner dump. On the basis of constructing the mechanical model of the intermediate bridge and the inner dump, using Mohr-Coulomb shear strength theory and soil pressure theory, the mathematical expressions of the variation of the supporting effect and the three-dimensional mechanical effect of the internal dump during the demolition of the intermediate bridge are derived, and the quantitative relationship between the dumping height and the demolition length of the intermediate bridge is obtained. Based on the idea of equivalence, a two-dimensional equivalent method for synergistic mechanical effect of inner dump is proposed, the influence of the height of the inner discharge pressure on the equivalent physical and mechanical parameters is revealed theoretically. The method is applied to Zahannaoer open-pit coal mine, the intermediate bridge demolition project was designed in stages and the slope stability of each stage was analyzed and verified. The results can lay a theoretical and application foundation for dynamic demolition design and engineering implementation of intermediate bridge in open-pit coal mine.