矿山岩体破坏微震分异速率特征及预警

Characteristics and Early Warning of Microseismic Differentiation Rate of Rock Mass Failure in Mines

在矿山岩体破坏预警研究中,探究岩体损伤特征规律及给出具体预警参数值对保障矿山安全至关重要。以某金属矿山为例,基于微震监测技术建立地压监测系统,结合该矿山某次顶板大范围冒落事件,采用主成分分析法确定最佳统计时间窗口,对顶板冒落事件前后微震时空演化特征进行分析。分析表明微震事件密度云图中心位置与破坏位置相一致,在岩体破坏前微震数量有持续增多,达到峰值后又迅速下降的前兆信息。以微震数量方差表示微震分异程度,以此表征岩体受损程度,采用有限差分法得出微震事件分异速率指标,结果表明,岩体破坏过程微震分异速率分为稳定分异阶段、加速分异阶段和岩体破坏三个阶段。稳定分异阶段分异速率呈正态分布,采用Gauss Amp函数对其进行拟合,最终得出置信度为0.99的置信区间,将区间上限0.306确定为分异速率预警值。该研究为采用微震监测技术的矿山灾害预警系统的建立提供理论基础,对矿山安全生产管理具有一定借鉴意义。

It is crucial to explore the characteristics of rock mass failure and provide specific early-warning parameter values to ensure mine safety in the study of early warning for rock mass damage in mines.This article takes a metal mine as example and establishes a ground pressure monitoring system using microseismic monitoring technology.The principal component analysis method is used to determine the optimal statistical time window and analyze the spatiotemporal evolution characteristics of microseisms before and after the roof caving event combined with a large-scale roof caving event in the mine.The analysis shows that the center position of the microseismic event density cloud map is consistent with the location of the failure,and there is a precursor information that the number of microseisms continues to increase before the rock mass failure,and rapidly decreases after reaching its peak.The microseismic differentiation degree was expressed by the microseismic quantity variance to represent the damage degree of rock mass.The microseismic differentiation rate index was obtained by using the finite difference method.The research shows that the microseismic differentiation rate of rock mass failure process was divided into three stages:stable differentiation stage,accelerated differentiation stage and rock mass failure stage.The Gaussian Amp function was used to fit it,and the upper limit of the confidence interval of 0.306 with a confidence level of 0.99 was determined as the early warning value for differentiation rate ultimately.This study provides a theoretical basis for the establishment of a mine disaster warning system using microseismic monitoring,and has reference significance for mine safety production management.