Deformation Mechanism And Disaster Analysis Of Overlying Rock In Mining With Transition From Pit To Underground

The problems such as the deformation of the rock slope overlying rockmass and the environmental damage to surroundings, which induced by transition exploration from open pit to underground, have developed into one of the most serious problems that affect the production and the environmental security. This article will perform numerical simulations and theoretical analysis about the mining process in Shangyu, which take the project about mining exploration from open pit to underground in Beijing Miyun Yunye as the backdrop and integrated the data of mining and the currently exploration into account, in order to explore the theoretical about the failure mechanism and the movement rule of the cover rock during the mining exploration from open pit to underground; determine the critical slip surface in slope based on the critical sliding field technology and estimate the slope stability and analyze, predict the disaster due to the instability and perform the field partition based on the different deformation by the support of three theories of limit equilibrium, and give some advice about how to prevent and control. The main research achievements as follows:1Established the three-dimensional numerical simulation model by MIDAS-3D; draw a conclusion about the distribution characteristics and varying pattern of stress and displacement fields by the research and numerical simulation of different areas and process of mining exploration.2)Take the stress and deformation fields in different mining steps, positions and exploration quantities into consideration to analyze the characteristics of distribution and differences and similarities; perform the research about the failure mode and movement features about the rock-mass slippage, and estimate the rock stability, get the conclusion that the emergency capacity of the steady state, which is connected with the rock-mass and the open pit affected by the superimpose effect due to open pit and underground, is decrease sharply. There are some potentially dangerous in rock-mass and open-pit slope in Shangyu.3)This article has systematically researched the variation features and rules of stress and displacement fields in different depths by analyzed mining in different space and areas, and has drawed the dynamical developing graph in the mine’s dangerous ranges, at the same time given some advice about how to prevent and control the frequently-occurred disasters.