Abstract:The stability of the open-pit mine slope is of great significance to the safe production of the mine. Under the long-term influence of blasting, the rock mass will cause damage accumulation. Therefore, this paper takes an open-pit mine in the Panxi area as the research object, and the blasting vibration obtained through on-site monitoring velocity, based on Flac3D numerical analysis software, to study the deformation characteristics and dynamic response characteristics of rock mass under dynamic blasting load, determine the dangerous area and design anchor cables for support analysis. The law of prestress loss under the action of blasting, the following conclusions are mainly drawn through the study: the slope under the action of blasting dynamic load produces local shear failure at the bottom of the slope and gradually develops along the upper part, and the blasting vibration response of velocity and displacement can be known by analyzing the monitoring data. The law is more consistent with the input wave. Under the action of multiple blasting, the maximum prestress loss ratio is 18.05%, and the prestress loss trend is gradually reduced. Therefore, the initial prestress value in the support design should be 1.2 of the design value. The research results provide a certain reference for the construction of open-pit mines.