Destabilized Mode And Control Technology Of Goaf Group In Xianglushan Tungsten Mine

The underground ore extraction could lead to many mined-out areas.For mines without strict control and standardized management,the irregular mined-out areas formed by disorderly mining cannot be effectively treated in time,resulting in many complicated and randomly distributed mined voids in underground ore bodies.In addition,due to the level of technology,the phenomenon of rich and poor abandonment was more serious in the early mining age,resulting in many valuable mineral resources being abandoned to the periphery of the goaf.With the continuous depletion of mineral resources and the improvement of mining technology,more and more attention is paid to the mineral resources left around the mined-out areas,and how to ensure the safety and stability of the goaf groups in the process of ore extraction is the major problems for mining companies.As such,the stability of the complex mined-out area group poses a considerable challenge to the safe exploitation of residual mineral resources.The current research on this issue is based on the simplified and approximate theoretical analysis of the stability of a single goaf,and most of the engineering practice applications are also based on empirical methods.The study of failure mode and failure development mechanism and the system stability of large-area complex goaf groups are limited.The thesis uses on-site investigation,theoretical derivation,experimental research,and numerical simulation to conduct in-depth research on single goaf and goaf groups with complex shapes,to obtain the spatial morphological characteristics of the goaf group and the destabilize mode,to reveal the chain development law of goaf failure and to propose the energy migration characteristics of the mined-out area group.Based on the proposed chain-breaking disaster reduction control technology,a set of "accurate void detection,spatial structure division,destabilized chain tracking,and backfill management" stability analysis and control technology for complex goaf group have been formed.The results have been verified by the engineering technology application in the Xianglushan Tungsten Mine.The main research contents are listed as follows:(1)The establishment of the spatial structure model of the goaf group in Xianglushan tungsten mine.By investigating the mining data of Xianglushan tungsten mine,the study on the spatial distribution form,geometric distribution characteristics and spatial structure mode of underground mined-out areas has been carried out combined with goaf detection,three-dimensional scanning and other methods,.Taking the Xianglushan tungsten mine goaf group as the engineering background,the three-dimensional shape,spatial location distribution,and pillar arrangement of the eastern test stope group were revealed,and the spatial structure model of the Xianglushan tungsten mine goaf group was established.(2)Proposed characteristics of the cut-out shape and the expression of the spatial relationship of the goaf group.Based on the spatial distribution law of occurrence and grade of metal mine ore bodies,the relationship between the spatial distribution characteristics of ore bodies and the morphology of the mined-out area have been investigated and revealed that the spatial morphological characteristics of the mined-out area are the general laws reflected by the local ore bodies.With the help of the fractal theory analysis method,the fractal law and characteristics of the spatial distribution of the mined-out area were studied,and the relationship between the fractal dimension value and the stress concentration of the rock mass in the mined-out area was revealed.The space division method based on the Voronoi diagram has been introduced and the expression of the spatial relationship of the goaf group has been proposed combined with the exhaustive search method of the goaf roof,(3)Establishment of a method to characterize the failure characteristics of the goaf group and the destabilized mode.The general characteristics and stability calculation methods of the failure of the pillars and roofs in the mined-out area have been studied,and the mechanical support structure model of the surrounding pillars under the disturbance of the environmental residual ore recovery in the mined-out area were established.The auto stress redistribution process between the roofs was analyzed to raise the identification method of the damage evolution and destruction state of the goaf roof and pillars,The destabilised mode of the goaf under dynamic disturbance was established to realize the state tracking and identification of the disaster process of the goaf group.(4)The proposed destabilization criteria induced by the goaf group catastrophe and the disaster chain development mechanism.The stress field and energy field change law of adjacent pillars and goaf groups after the failure of a single pillar were studied.The disturbance characteristics of adjacent goaf under a single destabilized goaf and the dependence of adjacent goafs and criteria for destabilizing induced under dynamic effects were revealed.Based on the catastrophic chain theory,the law of rock mass stress accumulation and transfer between surrounding rocks and pillars,and the characteristics of energy accumulation,transfer and dissipation during stress transfer were explored to reveal the "dominos" chain destabilized development mechanism in goaf groups.(5)Development of chain-breaking risk management and control technology for goaf group disaster.The catastrophic chain effect mode and termination conditions of the goaf group were studied,and the contradiction analysis method of the innovative method theory and the material-field analysis method related technical invention principles were used to reveal the root cause of the stability of the goaf group during the stoping process of the complex goaf group residual mine.Combined with the actual project of Xianglushan Tungsten Mine,the chain-breaking disaster reduction measures for the occurrence and development of the goaf group and the control technology for the goaf group have been developed,and the complex "domino"chain destabilise mode and control technology of the goaf group has been formed.And engineering technology verification has been carried out in Xianglushan tungsten mine.