Study On Surrounding Rock Disturbance Effect Of Multi-Middle Mining In Baixiangshan Iron Mine

As a high-efficiency and low-consumption mining mode,multi-middle mining is more and more widely used in metal mines.Especially for some large and thick orebodies,it has obvious advantages in expanding production scale and improving economic benefits.As a mining mode with practice ahead of theory,simultaneous multi-middle mining has not been clearly recognized and solved for its disadvantages such as difficult mining,severe disturbance,prominent ground pressure and poor safety of stope.At the same time,the laws of overlying strata migration and surface deformation in large-scale continuous mining,such as multi-middle mining,have also attracted much attention.Based on Baixiangshan Iron Mine,the disturbance and failure law of surrounding rock,the variation law of stress and displacement field,the stability of stope,the movement law of overlying strata and the dynamic movement and deformation law of surface under the combined mining mode of multi-middle section are analyzed by means of model test,numerical calculation and theoretical analysis.On this basis,the dynamic process of overburden movement and the mechanism of surface movement and deformation are analyzed,and the influencing factors of overburden movement and surface movement and deformation are summarized combined with the actual situation of Baixiangshan Iron Mine.Finally,based on stochastic medium theory,theoretical prediction of surface movement and deformation in multi-middle mining is carried out.Through the study in this paper,we will have a clear understanding of the disturbance effect of surrounding rock in multi-middle mining,which is of great significance and value to the wider and safer application of this mining model.The main conclusions are as follows:?1?Taking the geological mining conditions of Baixiangshan Iron Mine as the simulation prototype,the disturbance and failure of surrounding rock,the stability of stope,the stress change of surrounding rock and the movement law of overlying strata in the process of multi-middle mining are studied by using the similar model test method.A preliminary understanding of the disturbance law of surrounding rock in multi-middle mining is given.?2?On the basis of similar model test,FLAC^3D numerical simulation method is used to study the development of surrounding rock plastic zone,the change of stress field and displacement field,the movement and deformation of overlying rock and surface in the process of multi-middle mining.The dynamic movement and deformation law of overlying rock and surface under the geological mining conditions of Baixiangshan Iron Mine is obtained.?3?Based on the comparative analysis of similar model test and numerical simulation,the dynamic process of movement and deformation of overlying strata is summarized,and the mechanism of surface movement and deformation caused by overlying strata movement is analyzed.Combining with the actual project of Baixiangshan Iron Mine,the main factors affecting the movement and deformation of overlying strata and surface are given.?4?Based on the stochastic medium theory,the reasonable surface deformation parameters and calculation parameters are selected by engineering analogy method.The dynamic subsidence and horizontal movement of the surface in the process of multi-middle mining are predicted theoretically by using the main section model expression of surface movement and deformation in limited mining.Compared with the numerical simulation results,the theoretical prediction results are in good agreement with the simulation data,which shows that the prediction method can reasonably predict the surface movement and deformation in the process of multi-middle mining.