Abstract: The synchronous mining of open-pit and underground is a new mining method in recent years.Under the mining disturbance superimpose of two different excavation methods,the deformation and failure mechanism of slope rock mass is completely different from the slope stability problem under the action of single open pit mining.In this paper,based on the engineering example,it systematically reveals that the sliding deformation of the slope rock mass is the superposition of slip vector induced by two kinds of mining disturbance,and the deformation property depends on the action of each excavation disturbance.The movement characteristics of the composite deformation vector showed the property of large disturbance.But because the function of each kind of disturbance in different space position is different,it is shown that the evolution law of the slip mechanism after the superposition of the two kinds of action has the characteristics of division.According to characteristics of practical engineering exploitation,the numerical simulation method is used to systematically explore the rock slope slip characteristics and evolution rules of different mining combination to determine the scheme with minimum excavation disturbance,namely mining order from bottom to top.Under this scheme,the amount of displacement and the range of damage area are obviously smaller than the one from top to bottom.At the same time,the mechanism of slope sliding and the spatial properties of the slope rock mass deformation for the synchronous mining of open-pit and underground are studied,which provides a decision-making basis for the mining design and safety evaluation of similar mines.

Key words: Synchronous mining of open-pit and underground, Mining sequence, Slope stability, Deformation mechanism