Dynamic Instability Response And Control Of Minig Of Residual Ore In Goaf Group Based On Multi-Degree Of Freedom Model Method

Goaf is a major source of hazards for mines.Residual recovery is an effective way to increase resource recovery.During the secondary mining of the residual mineral resources,when the rock mass stress of the goaf group exceeds its ultimate strength and reaches the dynamic instability state,a series of disaster accident in the goaf group,including crushing of surrounding rock,falling of roof,and collapsing of surface,will occur.Therefore,it is of great significance to carry out the study on dynamic instability response and control of dynamic instability of the goaf group for ensuring the safe mining of mineral resources for the metal mine.The goaf group of a large integrated gold mine is taken as the research object.Based on the field survey,this paper use the theory of vibration mechanics,structural dynamics and numerical simulation method to carry out the study on dynamic instability response and control of the goaf group in the process of residue mining.The main works and research results are as follows:(1)On the basis of a survey on the general situation of underground goaf group in a large gold mine,the basical theory and method of structural dynamic response are studied.The methods included dynamic analysis theory,dynamic analysis model method and dynamic response equation analysis method.Then the dynamic instability response of single horizontal and longitudinal of the goaf group is analyzed.(2)Propose the multi-degree-of-freedom dynamic response model method for goaf group.The rationality of multi degree of freedom model method is verified by examples and monitoring results,and the dynamic response law of goaf group is analyzed.The spring module and damping module are used to deal with the cross linking problem between the roof and the columns in the empty group,which analysis results are more close to the essential characteristics of the engineering body.The Newmark-beta method and Matlab self compiled program have solved the problem of low computational efficiency and poor accuracy in the dynamic response of gob group.Compared with the numerical simulation method and the field displacement settlement results,the multi degree of freedom model method can directly reveal the dynamic response law of the goaf group.(3)According to the possible 16 kinds of remnant mining technology schemes in goaf group of a certain gold mine,combined with the multi-degree-of-freedom model method and the MIDAS/GTS numerical simulation method,the dynamic response characteristics of the goaf group are analyzed,and an optimal recovery plan is proposed.The results of the comprehensive analysis show that the scheme 3 is most suitable in the residual mining of the roofs in the goaf in the multi middle section,and the scheme 9 of the residual mining of the pillars of the goaf in the multi middle section is most suitable,and the scheme 12 in the residual mining of the roofs and the pillars of the goaf in the multi middle section is most suitable.(4)Separately construct the static characteristics and dynamic characteristics models,analyze the static characteristics and dynamic characteristic parameters of the goaf group after filling,evaluate and the effects after filling were comprehensively.The results of static characteristic parameters analysis show that the distribution range of tensile stress and compressive stress are shifted to the left and up,and the shear stress is completely transferred from the column to the filling body.The dynamic parameter analysis results show that the stress concentration within the goaf group has changed after filling,and the displacement and velocity response of the rock mass in the goaf group has dropped significantly.Comprehensive analysis shows that the goaf group has good dynamic stability after filling,and the research results provide theoretical guidance for dynamic instability engineering control during the mining process of the goaf group.