【作者】 罗文柯；

【导师】 施式亮；

【作者基本信息】 中南大学 ， 安全技术及工程， 2010， 博士

【摘要】 上覆火成岩,尤其是在巨厚火成岩(厚度h≥100m)下开采煤层,因巨厚火成岩而诱发的煤岩冲击、煤与瓦斯突出、巨厚火成岩断裂产生矿震等灾害日趋增多。随着开采深度不断向下延伸,埋藏在地层深部的火成岩对煤层开采影响越来越严重,安全威胁越来越大。在对典型巨厚火成岩突出灾害的研究中发现,突出灾害已经发生在传统理论下的非突出煤层和非突出危险区域。事实说明巨厚火成岩下突出矿井,已经表现出与无巨厚火成岩下突出矿井的异样性特点。因此,针对上覆巨厚火成岩条件的突出矿井,系统研究其突出灾害的一般规律、影响因素及其组合权重排序、突出风险性评价,提出科学合理预测预报体系及防治对策,已经成为当前煤矿安全、高效开采中急需完成的新课题。在广泛查阅国内外相关文献和系统总结前人研究成果的基础上,采用理论研究、实验室试验、数值模拟分析和现场实验相结合的研究方法,针对巨厚火成岩下突出矿井,基于其突出的力学机理、主要影响因素、危险性评价、多元指标预测及综合防突对策,展开了系统深入的研究,为巨厚火成岩下突出矿井煤炭资源的高效开采提供安全保障。(1)以材料力学和结构力学理论分析为基础,对巨厚火成岩下采掘扰动影响的覆岩移动规律进行了受力分析,提出了在巨厚火成岩下煤层开采后,在采场内巨厚火成岩将形成“两端固支梁”假说,并建立了巨厚火成岩下采动力学模型和变形本构方程。(2)以断裂力学理论为基础,视巨厚火成岩为“近似四边固支薄板”,利用仿纳维叶解法步骤,求得了在下覆煤层被采出后,巨厚火成岩中心点处最大挠度解析式Wmax和垂直方向最大正应力σxmax,为确保在煤层开采期间巨厚火成岩不破断的采区极限跨度确定提供了理论依据。(3)突出是煤体结构损伤失稳后的破坏现象,则以损伤力学理论为基础,对巨厚火成岩下煤层在三维应力作用下的损伤变量(D)进行分析,通过数学推导,求得在巨厚火成岩作用下煤层损伤变量D。的本构方程,以此通过反演法求得煤层的极限(最大允许)应力。(4)以典型矿井煤样和围岩及火成岩岩样为试件,在实验室对煤层瓦斯基本参数进行了测试,测试结果发现7、8、9煤为突出煤层；对7、8煤顶板岩样和火成岩岩样的冲击倾向性试验结果表明,8煤顶板具有强冲击性,火成岩的冲击倾向性评价为中强—强烈。(5)以典型巨厚火成岩突出矿井—海孜煤矿煤层赋存条件为背景,利用专门模拟地下岩体开挖工程的应力及应变的二维有限元软件Phase2,对典型巨厚火成岩下煤层群的采动情况进行了有和无巨厚火成岩两种情况的对比分析,通过模拟结果分析发现,在上覆巨厚火成岩条件下的垂直位移比无巨厚火成岩条件下要大；最大主应力比同等条件下无巨厚火成岩情况的最大主应力要小。(6)根据对典型巨厚火成岩突出矿井现场考察,建立了评价典型巨厚火成岩突出危险性指标体系,利用层次分析法原理对其影响因素进行了组合权重的排序和一致性检验发现,管理层面上的预测准确度和技术层面上的防突措施合理性为其主要影响因素,分别位居第1、2位。同时,以海孜煤矿为突出危险性评价对象,利用可拓法原理对其突出危险等级进行评估发现,上覆巨厚火成岩典型矿井属于突出等级(j0=4.54)。说明其突出危险性比无巨厚火成岩条件下要高出54%的概率。(7)在对巨厚火成岩下采掘扰动力学分析、突出灾害影响因素排序和危险等级评价的基础上,以灰色预测理论为指导,提出了在巨厚火成岩下突出灾害多元突出指标的综合预测体系,即对煤层敏感性指标Smax、K1、Δh2采用新陈代谢动态预测进行预测；对瓦斯涌出特征指标采用灰色—马尔柯夫组合模型进行预测；对巨厚火成岩在垂直方向的位移变形特征指标(高程损失量),采用LogisticⅠ/Ⅱ预测模型预测。并对典型突出案例“4·25"事故中前测试的实际数据进行预测应用研究发现,在无突出发生时,其预测值与实测值的相对误差α均在好的精度等级范围,而在突出灾害发生前,则相对误差超出精度α≥0.20。(8)以典型巨厚火成岩突出矿井—海孜煤矿为背景,在对巨厚火成岩利弊分析和影响因素极为复杂的基础上,提出了地面采动井抽采卸压瓦斯、网格穿层钻孔抽采卸压瓦斯、本煤层顺层钻孔抽采卸压瓦斯和高位巷(钻场)抽放卸压瓦斯的综合防治对策。在对Ⅱ1023工作面综合防突技术效果考察看,防突技术比较科学合理和实用,为海孜煤矿巨厚火成岩下煤炭资源开采提供了安全保障。更多还原

【Abstract】 Because of overlying igneous rocks, especially the very thick igneous rocks (the thicknessh≥100m), the coal rock shock, coal and gas outburst disasters and mine earthquake produced by very igneous rocks rupture are increasingly more when mining under the very thick igneous rocks. With the continuously downward extension of mining depth, the safety threat and effect to seam mining from igneous rocks buried deeply increases gradually. By researching the outburst disasters condition of the mine which is typical for the very thick igneous rocks, it is found that the disasters has occurred under the traditional theory of non-outburst coal seams and non-outburst regions. The facts proved that the unusual feature was happened under the very thick igneous rocks. Therefore, to systematic study the general laws of outburst disasters, effect factors, combine order of weights, outburst risk assessment and to put forward scientific and reasonable prediction and forecasting system and prevention measures, have become new urgent subjects needed to be completed with safety and efficient requirements.After widely consulted relevant literature and the previous research results home and broad, the mechanical mechanism of outburst disaster, main effect factors, risk assessment, multiple indexes prediction for the mine which very thick igneous rocks outburst are researched by using the method of theoretical research, laboratory experiment, numerical simulation analysis combined with field test. The safety guarantee for efficient mining of coal resources was provided.(1) Based on material mechanics and structural mechanics theory analysis, the mining disturbance on the effects of the law of overburden movement was analyzed. The hypothesis that the very thick igneous rocks will form clamped-clamped beam after mining the seams was put forward. Then the mining mechanical model and deformation constitutive equation under very thick igneous rocks were built.(2) Based on fracture mechanics theory, to treat the very thick igneous rock as a approximate quadrilateral thin plate, according to imitating Navier solution procedure, the maximum deflection of analytic Wmax in the central point of very thick igneous rocks and maximum vertical direction normal stressσxmax were obtained when the coal seams all mined. It provided theoretical basis for determining the limit mining region span to let the very thick igneous rocks not broken during the coal mining.(3) Outburst is the damage phenomenon of coal structure destruction. Based on the damage mechanics theory, the damage variable (D) of coal seams under the three dimension stress action was analyzed condition of the very thick igneous rocks. According to mathematical derivation, the constitutive equation of damage variable D总acting under very thick igneous rocks was obtained. Using inversion method, the maximum stress of coal seams was gained.(4) Through taking the typical coal samples, wall rocks and igneous rock samples as the pieces, the basic gas parameters of the coal seam are tested, the results show that the7th,8th and 9th coal seam are outburst coal seams; the test result of the impact trend, which is based on the test on the 7th,8th roof rock sample and igneous rock samples, shows that 8th roof is characterized by strong impact, and the impact of the igneous rocks is ranked from moderately strong to strong.(5) On the background of the occurrence condition of coal seams in Hai Zi mine, which is a very thick igneous rock outburst mine. According to the two dimensional finite element analysis program Phase, which is a special program used to perform the stress and strain of the rock after the excavation works, is used to make a comparison and analysis of the very thick igneous rocks covered mining condition and the condition not covered. It can be shown from the simulating results of the vertical displacement is greater when the coal seam is covered by very thick igneous rocks than the condition not covered, but the maximum main stress is smaller under the same conditions.(6) The risk index system of very thick igneous rock outburst is established through site inspection. Via using the theory of AHP to test the combination weight’s sorted and consistency of the effect factors, it is found that the prediction accuracy from the management level and the rationality of the outburst proof measures from the technology level are the main factors, these two ranks the first and the second. At the same time, utilizing the theory of extension method to assess the risk grade, it is found that Hai Zi mine is a very thick igneous rock outburst mine, which belongs to the grade of outburst, strictly speaking, j0 is 4.54 here. It means the risk degree is 54 percent higher than the condition not covered by very thick igneous rocks.(7) Based on mining disturbance mechanical analysis, effect factors sort of outburst disaster and risk grade assessment, under the guidance of the gray prediction theory, the metabolism dynamic prediction of the main sensitivity indicators, such as Smax, K,, Ah2, were brought up. The characteristic index of gas emission was predicted by the dynamic grey-Markoff model. Displacement deformation index(the elevation loss) was also predicted by the LogisticⅠ/Ⅱprediction model. The forecasting application of the actual measured data in the case of typical "4·25" accident has done, it is found that the relative errorαbetween prediction value and the real measured value of the gas emission quantity are in a good range of accuracy class when no outburst occur. But the relative error least exceeds 0.20 before outburst disaster broken out.(8) Hai Zi coal mine, which is a very thick igneous rock outburst mine, serves as a background basis. Based on the advantages and disadvantages of very thick igneous rock and the very complicated influencing factors, the four methods of sucking the relieved methane via surface mined shaft, via grid point drilling downward holes, via the holes drilled along seam in the coal seam and via high-level suction tunnels or drill site are presented. Via inspecting the technique effects of the measure in theⅡ1023 working face, it can be concluded that the technical proposal to control outburst is more scientific, reasonable and practical. And a safety control is provided to Hai Zi coal mine when mining under the very thick igneous rocks.更多还原