Bauxite Mine Goaf Group Under The Synergistic Action Of Weathering And Cyclic Blasting Instability And Control Research

The stability of the mined-out area is the basic condition for safe mining of underground mines.Due to the environmental characteristics of bauxite deposits,the rock masses in the mined-out areas are prone to weathering damage.Blasting operation is the main rock breaking method.With the continuous advancement of the working face,the blasting stress wave of adjacent stopes will affect the stability of the goaf group.The long-term cumulative damage will endanger the stability of the pillar and roof and induce The empty area group collapsed,causing the surface to collapse.Therefore,it is of great significance to carry out research on the instability and control of the bauxite goaf group under the synergistic effect of weathering and cyclic blasting,and to reduce the probability of mine engineering disaster accidents.This thesis takes a goaf group of an underground bauxite mine as the research object.Based on field investigation,the weathering damage factors of the goaf group are systematically analyzed.Based on structural dynamics,damage mechanics,and nonlinear theories,the weathering is constructed.The mechanical model of the damaged goaf group reveals the instability mechanism of the goaf group under the effects of weathering damage,joint damage,and cyclic blasting,and proposes control measures for the instability of the goaf group.The main work of the paper is as follows:(1)Investigate the weathering damage,the distribution of joints and cracks,and the blasting damage of the goaf group of bauxite mines.On this basis,analyze the deterioration and damage forms of the goaf group,and study the effects of these deterioration forms on the goaf area.Find the main controlling factors for the influence of group stability,and lay the foundation for the follow-up study on the overall long-term stability of the goaf group.(2)Construct a mechanical analysis model of the defect strip pillar structure in the goaf group.Based on the principle of energy dissipation and considering the influence of the internal crack propagation loose circle,the mathematical expression of the critical blasting load of the defective pillar support system is given to analyze the deterioration damage For the instability conditions of the goaf group,the relationship between the critical blasting load and the height and width of the pillar and the width of the loose zone of the crack zone is quantitatively studied.(3)Construct the structure model of the goaf group of bauxite mine,construct the displacement function of the goaf group,introduce the blasting stress wave damage factor Dn,characterize the damage effect on the rock mass under the blasting load,and use the stress displacement of the pillar and roof Based on the monitoring data,a method for judging the stability of the goaf group is proposed.(4)Combining the field survey results of the goaf group and the damage dynamic instability analysis result,the goaf group instability control analysis research is carried out from the three aspects of blasting single-stage charge control,short delay time control and waste rock filling.,Put forward the measures to control the instability of the goaf group.The research results of the thesis will provide theoretical support for the safe mining of underground bauxite mines and help improve the intrinsic safety of the mines...