Stability Analysis And Blasting Parameters Optimization In Deep Exploitation Of Deep Stope

With the increasing of mining depth,the mechanical environment faced by the deep metal mine mining turn into more complex.The vertical stress only caused by gravity is more than the compressive strength of the engineering rock mass when the mining depth exceeds one kilometer.In the high stress environment,the strong disturbance caused by frequent mining activities,special the medium-length hole blasting,would induce the geological hazard which threats safety of people and equipments.In deep mining process,dynamic response characteristics of rockmass caused by mining activities reflect the rationality of the blasting parameters which is related to stablity of surrounding rock.Therefore,studying the dynamic response law of rockmass based on capturing information of energy,deformation of surrounding rock and special-time evolution of fracture which can reveal the internal relations between surrounding rock and blasting parameters,offer scientific basis for optimation of blasting parameters,possesses important theoretical and practical significance.Relying on Hongtoushan Copper Mine,this paper establishes integrated deep stope monitoring system based on some monitoring technologies to capture information of energy,deformation of surrounding rock and special-time evolution of fracture in whole mining process for proposing evaluation index of blasting effect by adopting the method combinated of numerical simulation,field situ monitoring and application practice.The analysis of surrounding rock stability carries out considering the simulated results according to actual goaf morphology.On this basis,discussing the relation between stress distribution law and blasting parameters to establish evaluation index system contained multivariate information,and comprehensive evaluation method and technology of high stress induced blasting effect to optimize the blasting parameters.The feasiblity of optimization scheme for blasting parameters can be verified by economic benefit of the test stope.The specific studies were as follows:(1)Mechanics parameters of rock mass are determined by rock compressive strength,geological strength index of rock mass and other parameters based on uniaxial and triaxial loading tests and joint fissure survey technology.On this basis,adopts FLAC software to determine the reasonable mining sequence to obtain the stress distribution law according to rock stability and characteristics of construction organization.(2)According to structure of medium-length hole blasting stope and roadway layout,integrated deep stope monitoring system,constitute of cavity monitoring system,blasting vibration monitoring system,deformation monitoring system and microseismic(MS)monitoring system,to propose the evaluation index of blasting effect and capture information of energy,deformation of surrounding rock and special-time evolution of fracture in whole mining process based on development of continuous convergence deformation monitoring instrument for roadway,error analysis of spatial layout for seismic sensors according to D value criterion,installation design of recyclable seismic sensors,monitoring scheme formulation of goaf detection and vibration of blasting monitoring.(3)Attenuation law of microseismic events induced by mining disturbance is summaried on basis of Omori's power law aftershock sequences.Reasonable suggestions for time interval of stope mining blasting are proposed by the way of analyzing the change law of average energy of microseismic events,b value,emphatically,fractal dimension,spatial correlation length,cumulated microseismic energy release,and other parameters,discussing feasibility of surrounding rock stability evaluated by these microseismic parameters after blasting.(4)The mining process is simulated based on the goaf morphology obtained by cavity detecting system.Combined with monitoring data of microseismic and deformation of roadway,quantitative relation between microseismic parameters and goaf scale is systemic studied after analyzing stability of each zone in stope to reveal the inner link between evaluation index of medium-length hole blasting effect and mining.Considering law of stress distribution and evolution,pertinence support schemes for roadway in different zones are proposed after studying the difference of different zone surrounding rock and the possibility of different failure mode according to failure characteristics of roadway.(5)The safety index such as maximum blasting dosage of single segment,row spacing,bottom hole spacing,total dosage,horizontal distance and height,and some other parameters,are took the principal component analysis according to blasting vibration monitoring system.Combined with support vector machine method which is suitable for small sample,vibration velocity predicted model is established to reduce the dimension of input information for increasing of the generalization to improve the blasting dosage and enrich the blasting parameter optimization method.(6)Determination method of deep stope sequence is proposed according to microseismic monitoring data based on the study of high stress induced blasting adopted stress distribution law which obtained by microseismic monitoring.Evaluation index system contained multivariate information of high stress induced blasting effect is established to evaluate medium-length hole blasting effect of test stope,accompanied with the formation of comprehensive evaluation method and technology of high stress induced blasting effect.The feasiblity of optimization scheme for blasting parameters is verified by economic benefit of the test stope.