基于FLAC_3D_的复杂条件下露天转地下开采空区围岩变形及破坏特征

第42卷第6期中南大学学报(自然科学版) V ol.42No.6 2011年6月Journal of Central South University (Science and Technology) June 2011基于FLAC3D的复杂条件下露天转地下开采

空区围岩变形及破坏特征

史秀志,黄刚海,张舒,周健

(中南大学资源与安全工程学院,湖南长沙,410083)

摘要:针对铜绿山Ⅰ号矿体露天转地下开采的复杂情况,采用FLAC3D分析不同跨度D及立柱厚度d下采空区围岩的变形及破坏特征;用FISH语言定义岩石剪切破坏的摩尔−库仑判据,实现单元体剪切破坏判据值及其他关键参数在运算过程中的动态监测。依据研究结果,为施工设计提供合理工艺参数。研究结果表明:在空区上移过程中,空区顶板位移及围岩塑性变形区均先减小后增大;立柱稳固时,两者仅与空区跨度有关;立柱不稳固时,立柱厚度开始产生较大影响,跨度增大或立柱变薄,可使两者显著增大,并使空区在更大的顶柱厚度下便受到了露天坑底板压力的影响;立柱稳固时,空区破坏形式均为顶板两端剪切破坏;当跨度D=10 m,且立柱厚度d≤4 m 时,立柱开始不稳固,空区破坏形式逐渐转向立柱破坏。

关键词:采矿工程;采空区;围岩变形;剪切破坏判据

中图分类号:TD 325 文献标志码:A 文章编号:1672−7207(2011)06−1710−09

Goaf surrounding rock deformation and failure features using FLAC3D in underground mining shifted from open-pit in complex situation

SHI Xiu-zhi, HUANG Gang-hai, ZHANG Shu, ZHOU Jian

(School of Resources and Safety Engineering, Central South University, Changsha 410083, China)

Abstract: For the complex situation of orebody Ⅰ in Tonglvshan underground mining shifted from open-pit, the deformation and failure features of goaf surrounding rock under different spans D and column thickness d were carried out by FLAC3D software. Using FISH language to define Mohr-Coulomb criterion for rock shear failure, zone’s shear failure criterion and other key parameters in the course of calculation can be monitored. Lastly, according to the research results, reasonable process parameters for mining design are provided. The research indicates that during the process of goaf’s uppers shifting, the displacement of roofs and the area of rock’s plastic deformation reduce firstly, and then increase. When the column is steady, both of them are only related to span; When the column isn’t steady, column thickness has influence on them, the increase of span or the decrease of column thickness make them increase conspicuously, and cause that the goaf to be influenced by the pressure on open-pit floor under thicker pillar. When the column is steady, the form of goaf failure is that both ends of roof are shear failure; When span width D is 10 m and column thickness d≤4 m, the column is unsteady, and the form of goaf failure shifts to column failure.

Key words: mining engineering; goaf; rock deformation; shear failure criterion

矿体由露天转地下开采是目前国内部分露天矿面临的主要技术问题之一,而且这一问题随着矿体开采向深部延伸会更为突出。露天转地下开采工艺参数对地下采矿的安全性及矿产资源的损失量产生直接影

收稿日期:2010−06−10;修回日期:2010−08−28

基金项目:国家“十一五”科技支撑计划项目(2006BAB02A02);中南大学学位论文创新基金资助项目(2009ssxt230)

通信作者:史秀志(1966−),男,河北沙河人,博士,教授,从事采矿工程、爆破与安全方面的研究;电话:139********;E-mail:shixiuzhi@263.net

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