| The rockburst problem,which is induced by the increase of in-situ stress in metal mine more than 1000 meters below ground,become more and more prominent.The high in-situ stress causes lots of technical problems in deep mining.According to mining conditions of deposit and occurrence features of orebody,how to reasonably choose mining method and stope structure parameters to realize high-efficiency and safe production,and to ensure sustainable production of mine,is a key technical problem which is urgent to be solved by more and more metal mines now.This paper mainly researches mining in a lead-zinc mine.Firstly,rockburst proneness in mine is analyzed and determined through laboratory test and theoretical analysis method.Since the deposit with complex orebody morphology is deep and the deep tectonic stress is so strong that surrounding rocks are burst-prone,to ensure mine high-efficiency,safety and sustainable development,mining method optimization,stope structure parameters optimization and rockburst prediction in deep roadway after excavation are studied thoroughly and systematically by field investigation,theoretical analysis and numerical simulation.The contents and achievements of research mainly include:Part 1: On the basis of consulting geological data and site investigation,the physical and mechanical parameters of main ores and rocks from mining area are tested,and the rock mass physical and mechanical parameters are reduced from rock physical and mechanical parameters by Hoek-Brown criterion.The parameters provide accessible and accurate basic data for the subsequent analysis and calculation.Part 2: Four common indexes including rock brittleness index K,impact energy index W,elastic energy index WET and impact energy index WCF which characterize rockburst proneness are obtained by tests and calculation.And surrounding rocks' rockburst proneness is judged comprehensively by taking rock brittleness index K and impact energy index W as main indexes coupled with other indexes.Both theory and practice show that this kind of judgment method is objective and scientific.Part 3: Since the deposit with complex Orebody morphology is deep and the deep tectonic stress is so strong that burst-prone surrounding rocks are threats for future mining,five kinds of preliminary mining methods for the deposit are selected,then this paper appliedthe method of entropy weighting ideal point to the optimization of mining methods.Finally the upward horizontal cut and fill stoping method which comprehensively considers economic,technique and safety for the deposit is obtained.Part 4: The geometric model of stope is created by ANSYS/FLAC3 D coupled simulation.Stress distribution,vertical displacement and plastic zone which reveal stope stability after excavation or filling are simulated and calculated.Through optimization in term of safety and economy,four schemes including scheme four,scheme seven,scheme fourteen,scheme sixteen in which the stope is stable and production capacity is large are selected.Part 5: Stope structure parameters optimization model which is scientific and reliable is built combining fuzzy mathematics and AHP.The comprehensive fuzzy appraisal system which consists of eight evaluation indexes involved in economy,technique and safety is created,and then the superior degree values of these four preliminary schemes are obtained by calculation.As result,the superior degree of scheme fourteen is highest based on metric function.So this paper determine to adopt scheme fourteen that the mining entrance is 4m wide,4m long and filling method is cemented filling.Part 6: This paper comprehensively evaluates and forecasts rockburst in excavated roadway from both internal and external factors aspects.Based on judged rockburst proneness of surrounding rocks,the maximum principal stress distribution of excavated roadway in these two kinds of burst-prone rock mass is simulated and calculated.Besides,every critical depth corresponding to rockburst of adjacent levels is analyzed and judged through relevant theories. |
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