Study On The Wallrock Stability And Safety Control Of Deep Filling Stope In The Large Gold Mine

Taking deep mining in Jiaojia Gold Mine as the engineering background and the upward horizontal filling method as the research object,aiming at revealing the mechanism of surrounding rock deformation in deep mining of large gold deposits,the strength characteristics and damage evolution law of hard rock with deep joints,stability classification of deep surrounding rock,limit span of stope,deformation and stress evolution mechanism of surrounding rock with upward horizontal drift filling method,and control technology of stope stability are discussed.by means of laboratory mechanics experiment,theoretical analysis and numerical simulation.The following conclusions are obtained.(1)Through rock mechanics experiment and acoustic emission monitoring in laboratory,the change characteristics of AE parameters before and after rock failure are studied,and the damage evolution law of deep hard rock is obtained.The study shows that the AE parameters and damage of rocks show obvious phased change characteristics.On this basis,a damage constitutive model and strength criterion considering the inclination angle of a single joint are established.The results show that the total damage rate decreases first and then increases with the inclination angle of the joint,and the overall damage rate is in a positive U-shaped distribution.(2)The dominant joint groups of different approaches in Jiaojia mining area were obtained by using non-contact scanning system Shape Metrix 3D and Monte Carlo method.Then,the influence of different joint combinations on the stability of stope was analyzed based on block theory,and the unstable block and stress were determined.On this basis,based on the traditional RMR classification system,three correction coefficients including in-situ stress,joint combination and construction factors are added.A modified M-RMR classification method is proposed and applied in the field.The results show that the overall stability of ore and rock in Jiaojia mining area is at grade ?,some areas are at grade V,and the stability is poor.(3)Based on 3DEC software,a numerical calculation model reflecting actual joint distribution is established.Quantitative functional relationships among the grade of surrounding rock,mining depth and stope span,roof displacement and plastic zone are studied in the mining process of upward horizontal filling method.The results show that the stability grade of surrounding rock has the greatest influence on the displacement and damage of stope,and the displacement and the volume of plastic zone increase exponentially with the deterioration of stability.Based on the theory of pressure arch,the stress distribution of surrounding rock in the process of roadway mining is systematically studied.The results show that the stability level has a significant effect on the shape and arching coefficient of pressure arch.By using Mathews stability diagram method and combining with numerical simulation results,the limit span is calculated.The results show that the limit span of surrounding rock of grade ? should not exceed 5 m,and that of surrounding rock of grade ? should not exceed 4 m.(4)On the basis of experimental mining in Jiaojia Gold Mine and comprehensive research results in this paper,the control technology of surrounding rock of one-step mining room and anchor cable support of surrounding rock of two-step mining pillar are studied respectively.Finally,the comprehensive control technology of broken surrounding rock stability in deep filling mining is put forward.