采空区群的亚稳定“短板”单元甄别

尝试性的提出模态分析甄别方法,甄别金属矿采空区群的亚稳定"短板"单元。通过构建单元损伤与空区群结构模态参数之间的关系式,研究各单元的影响权值,评价空区各单元对群落整体稳定的影响。利用数值方法计算的应力、位移变化值,校验甄别结果。空区单元要素的分析结果表明,体积小、规整的空区影响权值小;体积大、围岩约束少的空区影响权值大,是系统亚稳定"短板"单元。间(顶)柱单元要素的分析结果表明,随着深度的增加,间柱对采空区群整体稳定性的影响逐渐增大,顶柱的影响则逐渐减小;浅部开采时,亚稳定"短板"单元多为顶柱,深部开采时,亚稳定"短板"单元多为间柱。该方法为甄别采空区群亚稳定"短板"单元提供了一条新的思路。

Short Board Metastable Unit Search Method for Group of Mined Out Area

A search method of modal analysis is provided from the point of damage theory's stiffness degradation to search “short board” metastable unit in mined out area of metal mines.The affecting weight of each unit is analyzed by constructing the comparison expression between unit damage and structural modal parameter,thus the influence of each unit in goaf on the whole stabilization of community can be evaluated.The variation values of stress and displacement which are calculated by utilizing numerical method can be used to verify and screen the results.The analysis results of goaf unit element show that the small volume and regular goaf have small affecting weight,the goaf which are large volume and less restriction of wall rocks have big affecting weight,and they are metastable “short board” units of system.The analysis result of spacer (top) pillar unit shows that with the increasement of depth,the effect of spacer pillar on the whole stabilization of goaf group is gradually increasing,while the effect of top pillar is gradually decreasing;when exploiting on the shallow part,metastable “short board” units mostly are top pillar,conversely,when exploiting in the deep part,they mostly are spacer pillar.