基于K-Means聚类与熵权TOPSIS法的岩石可爆性评价研究

Rock Blastability Evaluation based on K-Means Clustering and Entropy Weight TOPSIS Method

露天矿山的爆破块度分布,直接影响到后续的采装、运输和破碎工作。为了控制石墨矿山不同区域爆破块度分布,基于K-means无监督聚类学习法与熵权TOPSIS评价法建立了一种新的岩石可爆性评价模型,选取岩石密度、动力能量耗散率、动态抗压强度、平均应变率、脆性指数作为评价指标,通过熵权计算,发现岩石破碎程度受脆性指数影响最大,受平均应变率影响最小。将此模型应用于实际石墨矿山,可爆性分为10个等级,统计不同分级下的岩石平均破碎粒径,发现可爆性分级等级越高平均粒径越大,有明显的分级特征,验证了模型的有效性。从爆破石墨矿石岩体类型看,岩石可爆性从易到难排序为:片岩、片麻岩、变粒岩、混合岩。结合石墨矿石微观观测结果分析可知:岩性从片岩向混合岩转变,岩石内部石墨晶质呈下降趋势,石墨矿石可爆性等级也随之越来越高。岩石密度、能量耗散率、动态抗压强度之间呈线性正相关,岩石可爆性与平均应变率、脆性指数存在负相关性。研究成果为矿山矿岩可爆性评价提供了一条新思路,对露天矿山爆破块度优化具有一定的理论和实践指导意义。

The distribution of blasting fragmentation in open pit mines has a direct impact on subsequent excavation,transportation,and crushing operations.To effectively control the fragmentation distribution of blasted rocks in different regions of graphite mines,a new model for evaluating rock blastability was developed using the K-means unsupervised cluster learning method and entropy weight TOPSIS evaluation method.Evaluation indexes including rock density,dynamic energy dissipation rate,dynamic compressive strength,average strain rate,and brittleness index were selected.Through entropy weight calculation,it was determined that the degree of rock breakage is most influenced by the brittleness index and least influenced by the average strain rate.The model was then applied to an actual graphite mine to assess its effectiveness.The rock blastability was divided into 10 grades based on this evaluation model.The average particle size of rocks under different grades was calculated and it was observed that as blastability grade increased,so did the average particle size.This finding demonstrates clear classification characteristics and validates the efficacy of our model.From the perspective of rock mass type of graphite ore,the rock explosibility is ranked from easy to difficult:schist,gneiss,granodiorite,mixed rock.Combined with the analysis of microscopic observation results of graphite ore,it can be seen that the lithology changes from schist to mixed rock,and the graphite crystalline content in the rock decreases,and the graphite ore explosibility grade is also higher and higher.Additionally,there exists a linear positive relationship between density/energy dissipation rate/dynamic compressive strength with rock blastability while negative correlation is observed with respect to average strain rate/brittleness index.