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黄金科学技术 ›› 2019, Vol. 27 ›› Issue (2): 189-198.doi: 10.11872/j.issn.1005-2518.2019.02.189

• 采选技术与矿山管理 • 上一篇    

基于PFC2D-DFN的自然崩落法数值模拟研究

方传峰1,2,3(),王晋淼1,4,李剡兵5,贾明涛1,4   

  1. 1. 中南大学资源与安全工程学院,湖南 长沙 410083
    2. 长沙矿山研究院有限责任公司,湖南 长沙 410012
    3. 金属矿山安全技术国家重点实验室,湖南 长沙 410012
    4. 中南大学数字矿山研究中心,湖南 长沙 410083
    5. 云南迪庆有色金属有限责任公司,云南 香格里拉 674400
  • 收稿日期:2018-02-01 修回日期:2018-05-30 出版日期:2019-04-30 发布日期:2019-04-30
  • 作者简介:方传峰(1990-),男,山东泰安人,硕士研究生,从事矿山开采数值模拟分析研究工作。15084850237@163.com
  • 基金资助:
    国家重点研发计划项目“深部集约化开采生产过程智能管控技术”(编号:2017YFC0602905)

Numerical Simulation Research of Natural Caving Method Based on PFC2D-DFN

Chuanfeng FANG1,2,3(),Jinmiao WANG1,4,Shanbing LI5,Mingtao JIA1,4   

  1. 1. School of Resources and Safety Engineering,Central South University,Changsha 410083,Hunan,China
    2. Changsha Institute of Mining Research Co. ,Ltd. ,Changsha 410012,Hunan,China
    3. State Key Laboratory of Safety Technology of Metal Mines,Changsha 410012,Hunan,China
    4. Center of Digital Mine Research,Central South University,Changsha 410083,Hunan,China
    5. Yunnan Diqing Nonferrous Metal Co. ,Ltd. ,Shangri-La 674400,Yunnan,China
  • Received:2018-02-01 Revised:2018-05-30 Online:2019-04-30 Published:2019-04-30

摘要:

采用二维颗粒流软件PFC2D构建矿山模型,引入符合矿山实际节理产状的DFN网络,基于室内岩石试验及矿山实际崩落情况,标定模拟所用细观参数。以某工程应用为实例,模拟分析崩落破坏机理与崩落区演化趋势。结果表明:裂纹发起于推进面与顶板交界处,在拱形区域内密集扩展、贯通,矿岩破裂以节理拉伸破坏为主,矿堆以岩石剪切破坏为主;崩落区前期呈拱形演化,崩透地表后引起邻近高陡边坡滑动;部分拉底仅造成新开挖顶板上方局部崩落。该研究结果可对矿山崩落采矿起到指导作用。

关键词: 自然崩落法, 数值模拟, PFC2D软件, DFN, 拉底, 岩石破裂, 力学分析, 崩落演化

Abstract:

Surface subsidence and rock burst may occur during mining in mines using natural caving method,which affect the safety of mine production and the life safety of underground workers.Therefore,it is necessary to research the evolution law of caving area with the advance of undercutting.The research process of this paper is as follows.Firstly:using two-dimensional discrete element software PFC2D to construct a geometric model consistent with the actual topography of a mine.Secondly,according to the complete rock parameters obtained from laboratory mechanical experiments,by means of simulating physical experiments,the meso-parameters are continuously adjusted to approximate the actual physical parameters,the meso-mechanical parameters used in PFC2D are calibrated.In addition,according to the statistic law of joint sets distribution obtained on the spot,choose an appropriate joint generation method,make use of discrete fracture network DFN to reconstructe a joint model consistent with the statistical law.Then,based on the caving height of a certain period obtained by mine drilling television,the simulation results are approximated to the monitoring values by dichotomy method,and the corresponding joint strength parameters are back analyzed.Finally,the whole mine model is coupled with the joint model,and the particles and joints are assign property.After stress balance,the excavation is simulated.Statistic simulation results,the conclusions are as follows:Cracks first develop at the intersection of the undercutting advance working face and the roof,then extend,develop and penetrate in the arch region,resulting in crushing and collapse of the original rock.The main failure types of ore and rock are joint tensile failure,while shear failure often occurs in caved ore and rock.In the early stage,the caving area develops arch upward,which causes the adjacent steep slope to slide to the valley after penetrating the surface.In some undercutting steps,the caving area only occurs in the local area above the newly excavated undercutting region,which is consistent with the change trend of caving quality and roof height.

Key words: natural caving method, numerical simulation, PFC2D software, DFN, undercutting, rock failure, stress analysis, caving evolution

中图分类号: 

  • TD853.36

图1

矿山地形及地形轮廓线"

图2

PFC2D矿山模型"

表1

优势节理组产状统计结果"

组号占比/%倾向/(°)倾角/(°)
最大值最小值均值方差分布规律最大值最小值均值方差分布规律
136.36166120143.17126.89正态分布417971.7821.75正态分布
232.74196239216.2195.13正态分布447971.8619.83正态分布
35.41329306317.0735.58正态分布517569.2221.58正态分布
43.99314839.9923.69正态分布567770.5128.00正态分布

表2

节理间距与连续度统计结果"

项目最小值最大值均值标准差分布规律
节理间距0.001.380.0930.15对数正态分布
节理连续度0.0510.612.3500.37正态分布

表3

DFN产生所用参数"

节理分组节理与坑道单位长度交点数/个DFN节理倾角/(°)
最小值最小值均值标准差
10.36407071.784.67
20.33100136108.144.45
30.05104130110.784.64
40.04567770.525.29

图3

DFN生成离散节理局部放大图"

图4

DFN节理间距统计"

图5

单轴压缩试验曲线图"

图6

三轴伺服压缩试验曲线图"

表4

岩石实际物理力学参数与岩石模拟物理力学参数对照表"

对比参数试验结果模拟值误差/%
弹性模量/GPa54.5854.290.53
泊松比0.270.263.70
抗压强度/MPa127.96125.931.60
黏聚力/MPa22.0624.8312.50
摩擦角/(°)47.849.002.50

表5

模拟采用细观参数"

参数类型参数名数值
密度/(kg·m-32 700
线性参数弹性模量/GPa48.0
刚度比1.0
摩擦系数1.0
平行粘结参数弹性模量/GPa9.0
刚度比2.5
抗拉强度/MPa75.0
黏聚力/MPa25.0
摩擦角/(°)75.0
半径系数1.5

图7

节理参数标定流程图"

表6

节理参数"

参数名称数值参数名称数值
法向刚度/GPa6.0摩擦角/(°)25
切向刚度/GPa3.0抗拉强度/MPa0.7
黏聚力/MPa7.0

图8

第一步拉底裂纹扩展"

图9

裂纹扩展与破裂类型统计"

图10

崩落区形态演化特征"

图11

崩落区统计图"

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