Research On Instability Of Goaf Group Based On The Frame-like Structure Model

A large number of unprocessed goaf groups were left behind after underground mining.Compared to single goaf,goaf group was bigger and wider,and its stress distribution was more complex.Goaf group had multiple influence factors,disasters and accidents caused by its instability were characterized by poor foresight,serious consequences and so on.The instability of single goaf was likely to induce the instability of the whole goaf group,then resulted in serious losses to people and property.Therefore,in order to improve the intrinsic safety of metal mines and prevent disaster accidents,it is urgent to carry out the research on instability analysis method and the key factors of the goaf group.In this paper,a large-scale goaf group of a underground gold mine was taken as the research object.Based on the data inspection and on-the-spot investigation,the frame-like structure model of the goaf group was constructed.Then the stability analysis of goaf group and the research on stoping scheme of residual ore were carried out.The main contents and achievements of this paper were as follows:(1)The goaf group and the frame structures were compared,the similarities and differences between them were explicit.Based on the abstract of roof,pillar,constraints and connection modes,the frame-like structure model of the goaf group was constructed.(2)Based on the the frame-like structure model of the goaf group,the safety factor expression of pillar,roof and goaf group were established respectively,range analysis was applied to obtain the importance ranking of the goaf group's various influence factors,main control factors and corresponding critical values,then qualitative stability evaluation of the goaf group was attempted.(3)The frame-like structure models of the goaf group before and after mining were constructed,then the displacement and stress of their key points were calculated by the improved QR method,finally applying instability criterion of pillar and roof to study the global stability of the goaf group.(4)Taking the double rows goaf group and three rows goaf group of KT5 orebody as research object,comprehensively appling the instability analysis method of the goaf group based on the frame-like structure model and numerical analysis method to study their instability under under various mining schemes,then made reasonable mining plan.The research results provide a new theoretical method for the instability analysis of the goaf group,which had certain theoretical guiding function.