鄂西缓薄赤铁矿采场稳定性分析及参数优化
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摘要
论文简述了我国铁矿石的需要状况,分析了我国矿山开采的发展趋势,同时针对一类难采矿体—缓倾斜薄矿体,总结了开采该类矿体时所使用的采矿方法,其中,房柱采矿法所占的比例最高。鉴于此,本文以房柱采矿法为例,对采场进行简化后,利用相关力学理论对顶板及矿柱稳定性进行了分析,得到了采场中各物理量的分布规律。然后利用有限差分软件FLAC3D,针对水平矿体的开采,建立了两种采场结构模型：
(1)考虑到铲运机能在相邻矿房间来回作业,将矿柱间距固定为4m。
(2)矿房跨度与矿柱间距尺寸相等；
分别对以上两种结构形式的采场进行了数值模拟,比较了在同样回收率条件下,顶板中最大拉应力值的大小,并选较小拉应力的结构形式进行后续分析。本文选取第二种采场结构模型并进一步对其进行数值模拟,分析了矿岩物理力学性质、地应力、采场结构参数对房柱法采场稳定性的影响,得到如下结论：
(1)选取了两种力学性质差别较大矿岩进行了数值模拟,发现采场中各物理量分布的差别不大,但矿岩自身的力学性质的限制影响了开采的安全性。
(2)对于地应力对采场安全的影响,通过数值模拟得出：采场周围较大的水平侧向应力对维护顶板中央的稳定性有利,垂直应力(赋存深度)的增大导致了顶板中最大拉应力的增加以及矿柱平均垂直应力的线性增长,加速了顶板和矿柱的破坏。
(3)采场结构参数的影响主要表现为：矿房高度对采场顶板的稳定性基本没有影响,同时矿柱平均压应力随高度的增大仅有微弱的增大,但对矿柱稳定性的影响主要体现在矿柱支撑能力的变化上,因为矿柱高度的增加降低了矿柱的支撑能力(尺寸效应)；矿房跨度的增大时,顶板最大拉应力增大,且增加幅度越来越大；在矿房跨度较小时,矿柱宽度的变化顶板最大拉应力基本上没有影响,但在跨度较大时,增大矿柱宽度能降低顶板最大拉应力。
最后,针对鄂西缓薄高磷赤铁矿,通过数值模拟,得到了不同深度下的采场最优结构参数,并计算得到了矿石回收率,进而通过线性回归得到回收率随深度变化的函数关系。
Demand status of iron ore in our country is briefly stated in this paper, and development tendency of domestic mining is analyzed, meanwhile, mining methods used to mine gentle dip thin ore which can't be easily mined are summarized, among which the proportion of room-and-pillar mining method is highest. In view of this, taking the mining method for example, related mechanics theory is used to analyze the stability of roof and pillar after the simplification of stope, and the distribution rule of each physical quantity(stress, displacement) is obtained. Then two forms of stope structure of horizontal ore are established with FLAC3D, a finite difference software in the paper:
(1) Considering that carry-scraper can make a round work in adjacent stope, the pillar gap is fixed as 4m,
(2) Room span is equal to pillar gap.
Then numerical simulation of the two forms is conducted respectively, making a comparison of the maximum tension stress in roof in the condition of the same recovery, and the smaller one is chosen for following analysis. The second form are selected for further numerical simulation. Then the influence of physical and mechanical properties of ore and rock, geo-stress, stope structure parameter to the stability of stope is analyzed respectively, and the results are shown as following:
(1)Two kinds of ore, the mechanical properties of which are greatly different, are chosen for numerical simulation in the paper, the results of which shows that the physical quantities slightly vary, but the mechanical properties of ore itself influence the safety of mining.
(2)For the influence of geo-stress to stope safety, it can be drawn from numerical simulation that high horizontal stress around the stope is favorable to sustain the stability in the center of roof, the increase of vertical stress (depth) leads to the increase of maximum tension stress in roof and the linear increase of pillar average vertical stress, which accelerates the break of roof and pillar.
(3)The influence of stope structure parameters mainly can be concluded as:there is little influence of the room height to stope roof, at the same time, along with the increase of depth, there is a little increase in average stress of pillar. But to the influence of pillar stability, it mainly reflected in the variations of pillar supporting capacity, because the increase of pillar height decreased pillar supporting capacity (size effect). The maximum tension stress increases with the room span and the increasing range become larger. When the room span is small, there is little influence of width of pillar to the maximum tension stress, but when the span is big enough, increasing the width can decrease the maximum tension stress of roof.
Finally, aiming at gentle inclined thin ore body in Western Hubei, using numerical simulation, optimum structure parameters and ore recovery are obtained, then the functional relationship between recovery and depth is gained.
(1)考虑到铲运机能在相邻矿房间来回作业,将矿柱间距固定为4m。
(2)矿房跨度与矿柱间距尺寸相等；
分别对以上两种结构形式的采场进行了数值模拟,比较了在同样回收率条件下,顶板中最大拉应力值的大小,并选较小拉应力的结构形式进行后续分析。本文选取第二种采场结构模型并进一步对其进行数值模拟,分析了矿岩物理力学性质、地应力、采场结构参数对房柱法采场稳定性的影响,得到如下结论：
(1)选取了两种力学性质差别较大矿岩进行了数值模拟,发现采场中各物理量分布的差别不大,但矿岩自身的力学性质的限制影响了开采的安全性。
(2)对于地应力对采场安全的影响,通过数值模拟得出：采场周围较大的水平侧向应力对维护顶板中央的稳定性有利,垂直应力(赋存深度)的增大导致了顶板中最大拉应力的增加以及矿柱平均垂直应力的线性增长,加速了顶板和矿柱的破坏。
(3)采场结构参数的影响主要表现为：矿房高度对采场顶板的稳定性基本没有影响,同时矿柱平均压应力随高度的增大仅有微弱的增大,但对矿柱稳定性的影响主要体现在矿柱支撑能力的变化上,因为矿柱高度的增加降低了矿柱的支撑能力(尺寸效应)；矿房跨度的增大时,顶板最大拉应力增大,且增加幅度越来越大；在矿房跨度较小时,矿柱宽度的变化顶板最大拉应力基本上没有影响,但在跨度较大时,增大矿柱宽度能降低顶板最大拉应力。
最后,针对鄂西缓薄高磷赤铁矿,通过数值模拟,得到了不同深度下的采场最优结构参数,并计算得到了矿石回收率,进而通过线性回归得到回收率随深度变化的函数关系。
Demand status of iron ore in our country is briefly stated in this paper, and development tendency of domestic mining is analyzed, meanwhile, mining methods used to mine gentle dip thin ore which can't be easily mined are summarized, among which the proportion of room-and-pillar mining method is highest. In view of this, taking the mining method for example, related mechanics theory is used to analyze the stability of roof and pillar after the simplification of stope, and the distribution rule of each physical quantity(stress, displacement) is obtained. Then two forms of stope structure of horizontal ore are established with FLAC3D, a finite difference software in the paper:
(1) Considering that carry-scraper can make a round work in adjacent stope, the pillar gap is fixed as 4m,
(2) Room span is equal to pillar gap.
Then numerical simulation of the two forms is conducted respectively, making a comparison of the maximum tension stress in roof in the condition of the same recovery, and the smaller one is chosen for following analysis. The second form are selected for further numerical simulation. Then the influence of physical and mechanical properties of ore and rock, geo-stress, stope structure parameter to the stability of stope is analyzed respectively, and the results are shown as following:
(1)Two kinds of ore, the mechanical properties of which are greatly different, are chosen for numerical simulation in the paper, the results of which shows that the physical quantities slightly vary, but the mechanical properties of ore itself influence the safety of mining.
(2)For the influence of geo-stress to stope safety, it can be drawn from numerical simulation that high horizontal stress around the stope is favorable to sustain the stability in the center of roof, the increase of vertical stress (depth) leads to the increase of maximum tension stress in roof and the linear increase of pillar average vertical stress, which accelerates the break of roof and pillar.
(3)The influence of stope structure parameters mainly can be concluded as:there is little influence of the room height to stope roof, at the same time, along with the increase of depth, there is a little increase in average stress of pillar. But to the influence of pillar stability, it mainly reflected in the variations of pillar supporting capacity, because the increase of pillar height decreased pillar supporting capacity (size effect). The maximum tension stress increases with the room span and the increasing range become larger. When the room span is small, there is little influence of width of pillar to the maximum tension stress, but when the span is big enough, increasing the width can decrease the maximum tension stress of roof.
Finally, aiming at gentle inclined thin ore body in Western Hubei, using numerical simulation, optimum structure parameters and ore recovery are obtained, then the functional relationship between recovery and depth is gained.
引文
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[3]李俊平,冯长根,郭新亚,等.矿柱参数计算研究[J].北京理工大学学报,2002,22(5)：662-664.
[4]尤明庆,华安增.岩样单轴压缩的尺度效应和矿柱支承性能[J].煤炭学报,1997,22(1)：37-41.
[5]万虹.地下空区稳定性的相似模拟研究[J].岩土工程学报,1998,20(6)：74-77.
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[7]孔德森,栾茂田.岩土力学数值分析方法研究[J].岩土工程技术,2005,19(5)：249-253.
[8]施建俊,孟海利.采场结构参数与回采顺序的数值模拟优化研究[J].有色金属(矿山部分),2005,57(2):9-11.
[9]吴洪词、胡兴、包太.采场围岩稳定性的FLAC算法分析[J].矿山压力与顶板管理,2002,(4)：96-98.
[10]孙国权、李娟、胡杏保.基于FLAC3D程序的采空区稳定性分析[J].金属矿山,2007,(2):29-32.
[11]张晓君,黄河.矿柱及围岩非均质性对采空区破坏过程的影响[J].金属矿山,2007,(6)：22-24.
[12]郭忠林,王家齐.房柱采矿法结构尺寸的模拟研究[J].昆明工学院学报,1992,17(1)：20-29.
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[18]A.A.Baryakh, N.A.Samodelkina. To the calculation of pillar stability under condition of chamber mining[J]. Journal of Mining Science,2007,43(1):8-16.
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[20]A. Jaiswal, S. K. Sharma, B. K. Srivastva. Numerical modeling study of asymmetry in the induced stresses over coal mine pillars with advancement of the goaf line[J]. International Journal of Rock Mechanics and Mining Science,2004,41(5):859-864.
[21]S. V. Makarov. Rock pressure control in working a wide pillar by breast stoping with stowing[J]. Journal of Mining Science,1975,11(3):238-241.
[22]V. B. D'yakovskii and M. F. Chernyshev. The state of stress in virgin rock and pillars in the vysokogorsk iron-ore deposit studied by the deloading method[J]. Journal of Mining Science, 1968,4(2):178-180.
[23]Davide Elmo, Doug Stead. An Integrated Numerical Modelling-Discrete Fracture Network Approach Applied to the Characterisation of Rock Mass Strength of Naturally Fractured Pillars[J]. Rock mechanics and Rock Engineering,2010,43(1):3-19.
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[26]B. A. Zhukov. Pressure exerted by cut coal and stowage in pillar working to the rise[J]. Journal of Mining Science,1966,2(1):107-111.
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[28]胡际平.国外空场采矿法的发展及其借鉴意义[J].金属矿山,1990,(1)：17-22.
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[30]卢光远,孙宏生,刘让,等.无轨设备在房柱法盘区中的应用[J],2007,(8)：188-190.
[31]高磊.矿山岩体力学[M].北京：冶金工业出版社,1979.
[32]杨耀乾.平板理论[M].北京：中国铁道出版社,1980.
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[2]吴法春.缓倾斜矿体回采时矿柱设计与岩石力学[J].有色金属(矿山部分),2002,54(5),19-20.
[3]李俊平,冯长根,郭新亚,等.矿柱参数计算研究[J].北京理工大学学报,2002,22(5)：662-664.
[4]尤明庆,华安增.岩样单轴压缩的尺度效应和矿柱支承性能[J].煤炭学报,1997,22(1)：37-41.
[5]万虹.地下空区稳定性的相似模拟研究[J].岩土工程学报,1998,20(6)：74-77.
[6]冯现珍,周铿伦.缓倾斜薄至中厚矿体开采中矿柱设计依据的初探[J].有色金属(矿山部分),1996,(5)：7-9.
[7]孔德森,栾茂田.岩土力学数值分析方法研究[J].岩土工程技术,2005,19(5)：249-253.
[8]施建俊,孟海利.采场结构参数与回采顺序的数值模拟优化研究[J].有色金属(矿山部分),2005,57(2):9-11.
[9]吴洪词、胡兴、包太.采场围岩稳定性的FLAC算法分析[J].矿山压力与顶板管理,2002,(4)：96-98.
[10]孙国权、李娟、胡杏保.基于FLAC3D程序的采空区稳定性分析[J].金属矿山,2007,(2):29-32.
[11]张晓君,黄河.矿柱及围岩非均质性对采空区破坏过程的影响[J].金属矿山,2007,(6)：22-24.
[12]郭忠林,王家齐.房柱采矿法结构尺寸的模拟研究[J].昆明工学院学报,1992,17(1)：20-29.
[13]科茨.岩石力学原理[M].雷华南.北京：冶金工业出版社,1995.
[14]J. Butral, W. Pytel. Copper mine roof-pillar-floor behavioral assessment based on in-situ measurements and numerical modeling [J]. Int. J. Rock Mech. Min. Sci,2004,41(3):1-6.
[15]Daniele Peila, Claudia Guardini, Sebastiano Pelizza. Geomechanical design of a room and rib pillar granite mine [J]. Journal of University of Science and Technology Beijing,2008, 15(2):97-103.
[16]M.A.Lin'kov. On the theory of pillar design[J]. Journal of Mining Science,2001,37(1):10-27.
[17]Christopher Alford, Marcus Brazil, David H.Lee. Optimisation in underground mining. 561-577.
[18]A.A.Baryakh, N.A.Samodelkina. To the calculation of pillar stability under condition of chamber mining[J]. Journal of Mining Science,2007,43(1):8-16.
[19]Wilson, A., Ashwin. Research into the determination of pillar size. The Mining Engineer, 1972,131:409-417.
[20]A. Jaiswal, S. K. Sharma, B. K. Srivastva. Numerical modeling study of asymmetry in the induced stresses over coal mine pillars with advancement of the goaf line[J]. International Journal of Rock Mechanics and Mining Science,2004,41(5):859-864.
[21]S. V. Makarov. Rock pressure control in working a wide pillar by breast stoping with stowing[J]. Journal of Mining Science,1975,11(3):238-241.
[22]V. B. D'yakovskii and M. F. Chernyshev. The state of stress in virgin rock and pillars in the vysokogorsk iron-ore deposit studied by the deloading method[J]. Journal of Mining Science, 1968,4(2):178-180.
[23]Davide Elmo, Doug Stead. An Integrated Numerical Modelling-Discrete Fracture Network Approach Applied to the Characterisation of Rock Mass Strength of Naturally Fractured Pillars[J]. Rock mechanics and Rock Engineering,2010,43(1):3-19.
[24]G. T. Nesterenko, B. S. Skozobtsov and R. K. Tverdovskii. Method for assessing the strength properties of rocks in pillars[J]. Journal of Mining Science,1971,7(6):702-704.
[25]E. F. Zhitkov. Calculation of the widths of rooms and pillars with roof control by convergence on yielding pillars[J]. Journal of Mining Science,1975,11(1):17-22.
[26]B. A. Zhukov. Pressure exerted by cut coal and stowage in pillar working to the rise[J]. Journal of Mining Science,1966,2(1):107-111.
[27]张世雄.矿物资源开发工程[M].武汉：武汉理工大学出版社,2000.
[28]胡际平.国外空场采矿法的发展及其借鉴意义[J].金属矿山,1990,(1)：17-22.
[29]何正忠.我国地下矿山无轨设备的十年历程和发展趋势[J].长沙矿山研究院季刊,1986,6(4)：176-181.
[30]卢光远,孙宏生,刘让,等.无轨设备在房柱法盘区中的应用[J],2007,(8)：188-190.
[31]高磊.矿山岩体力学[M].北京：冶金工业出版社,1979.
[32]杨耀乾.平板理论[M].北京：中国铁道出版社,1980.
[33]钱鸣高,刘听成.矿山压力及其控制[M].北京：煤炭工业出版社,1991.
[34]何富连.采场岩层控制论[M].北京：冶金工业出版社,2009.
[35]杨立根.岩石力学在缓倾斜矿体开采中的应用[J].长沙矿山研究院季刊,1986,6(4)：55-62.
[36]郑永学.矿山岩体力学[M].北京：冶金工业出版社,1988.
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