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| INTACT-LOOSE MEDIUM EQUIVALENT TRANSFORMATION AFTER COUPLED CRACKING AND ASSESSMENT OF CAVING CAPABILITY |
| CUI Feng1，2，LAI Xingping1，2，CAO Jiantao1，2，SHAN Pengfei1，2 |
| (1. School of Energy，Xi?an University of Science and Technology，Xi?an，Shaanxi 710054，China；2. Key Laboratory of Western Mines and Hazard Prevention of Ministry of Education，Xi?an University of Science and Technology，Xi?an，Shaanxi 710054，China) |
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Abstract A discrete element model(DEM) of describing the equivalent strength of coal mass after cracking due to the coupled action was established for the quantitative evaluation of the effect of cracking due to coupled action. The overall strength was taken as an index to achieve the equivalent transformation of discretization of intact to loose coal mass. The caving of the top coal and the flow pattern were researched with DEM. The hinge relationship of discrete particles and its influence to caving after coupled cracking were analyzed. The relationship between the caving and flowing capacity of coal mass，the parameters of explosive load and the injecting pressure of water was quantified and the result was verified in an engineering practice. The essence of coupled cracking was the spreading of the gas and blast wave generated in the explosion in the softened coal-rock. The overall strength of coal-mass was regarded as an equivalent conversion index for the equivalent transformation between the different algorithms for coal-mass. The method of coupled cracking increased the caving effect of coal-mass by reducing the tensile stress of blocks and the amount of contact between particles. The strength of coal mass for fully caving and the peak strength meeting the requirements of recovery ratio for the thick coal seam were obtained. The quantitative assessment of coupled cracking in coal mass under the complex environment was accomplished.
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Received: 10 July 2014
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| [1] 谢和平，王家臣，陈忠辉，等. 坚硬厚煤层综放开采爆破破碎顶煤技术研究[J]. 煤炭学报，1999，24(4)：350–354.(XIE Heping，WANG Jiachen，CHEN Zhonghui，et al. Study on top-coal blasting technique of full-mechanized caving in the hard thick coal seam[J]. Journal of China Coal Society，1999，24(4)：350–354.(in Chinese))
[2] 张子飞，来兴平. 复杂条件下急斜厚煤层高阶段综放开采超前预爆破[J]. 煤炭学报，2008，33(8)：845–849.(ZHANG Zifei，LAI Xingping. Segment pre-blasting of sublevel caving of steep and thick coal seam under complex conditions[J]. Journal of China Coal Society，2008，33(8)：845–849.(in Chinese))
[3] CUI F，LAI X P，CAO J T. Analysis of weakening effect of pre-blasting in top coal of steep and thick seams based on nonlinear dynamics[C]// CAI Meifeng ed. Proceedings of the 2nd ISRM International Young Scholar? Symposium on Rock Mechanics：Achievements and Ambitions. London：Taylor and Francis Inc.，2012：775–778.
[4] 康天合，张建平，白世伟. 综放开采预注水弱化顶煤的理论研究及其工程应用[J]. 岩石力学与工程学报，2004，23(15)：2 615–2 621. (KANG Tianhe，ZHANG Jianping，BAI Shiwei. Theoretical study and application of weakening top coal using water pre-infusion in fully mechanized sublevel caving mining[J]. Chinese Journal of Rock Mechanics and Engineering，2004，23(15)：2 615–2 621.(in Chinese))
[5] 邓广哲. 煤层裂隙应力场控制渗流特性的模拟实验研究[J]. 煤炭学报，2000，25(6)：593–597.(DENG Guangzhe. Study on seepage features of coal-bed cracks under controlling stress[J]. Journal of China Coal Society，2000，25(6)：593–597.(in Chinese))
[6] HUANG B X，LIU C Y，FU J H，et al. Hydraulic fracturing after water pressure control blasting for increased fracturing[J]. International Journal of Rock Mechanics and Mining Sciences，2011，48(6)：976–983.
[7] Itasca Consulting Group Inc.. PFC2D(Particle flow code in 2 dimensions) online manual table of contents[R]. Minnesota：Itasca Consulting Group Inc.，2003.
[8] XIE Y S，ZHAO Y S. Numerical simulation of the top coal caving process using the discrete element method[J]. International Journal of Rock Mechanics and Mining Sciences，2009，46(6)：983–991.
[9] FERHAN S，MUHARREM K O. Determination of the most effective longwall equipment combination in longwall top coal caving(LTCC) method by simulation modelling[J]. International Journal of Rock Mechanics and Mining Sciences，2008，45(6)：1 015–1 023.
[10] KULATILAKE P H S W，BWALYA M，WANG J L. Physical and particle flow modeling of jointed rock block behavior under uniaxial loading[J]. International Journal of Rock Mechanics and Mining Sciences，2001，38(5)：641–657.
[11] POTYONDY D O，CUNDALL P A. A bonded-particle model for rock[J]. International Journal of Rock Mechanics and Mining Sciences，2004，41(8)：1 329–1 364.
[12] 吴顺川，周 喻，高利立，等. 等效岩体技术在岩体工程中的应用[J]. 岩石力学与工程学报，2010，29(7)：1 435–1 441.(WU Shunchuan，ZHOU Yu，GAO Lili，et al. Application of equivalent rock mass technique to rock mass engineering[J]. Chinese Journal of Rock Mechanics and Engineering，2010，29(7)：1 435–1 441.(in Chinese))
[13] 吴顺川，周 喻，高 斌. 卸载岩爆试验及PFC3D数值模拟研究[J]. 岩石力学与工程学报，2010，29(增2)：4 082–4 088.(WU Shunchuan，ZHOU Yu，GAO Bin. Study of unloading tests of rock burst and PFC3D numerical simulation[J]. Chinese Journal of Rock Mechanics and Engineering，2010，29(Supp.2)：4 082–4 088.(in Chinese))
[14] 靳钟铭，康天合，弓培林，等. 煤体裂隙分形与顶煤冒放性的相关研究[J]. 岩石力学与工程学报，1996，15(2)：143–149.(JIN Zhongming，KANG Tianhe，GONG Peilin，et al. Interrelation of crack fractal to top coal caving and drawing characteristics[J]. Chinese Journal of Rock Mechanics and Engineering，1996，15(2)：143–149.(in Chinese))
[15] 王家臣. 厚煤层开采理论与技术[M]. 北京：冶金工业出版社，2009：88–102.(WANG Jiachen. The theory and technique on the thick coal seams mining[M]. Beijing：Metallurgical Industry Press，2009：88–102.(in Chinese)) |
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2015, Vol. 34 
