【作者】 王海东；

【导师】 景立平；

【作者基本信息】 中国地震局工程力学研究所 ， 岩土工程， 2012， 博士

【摘要】 我国煤系地层普遍埋藏较深，赋存条件复杂，并且煤层瓦斯含量高，吸附性强，煤层松软，透气性较差，瓦斯抽采困难。随着我国对煤炭需求量的增加，开采强度不断增大，浅部资源日益减少，深部开采矿井数量逐渐增多。我国煤矿开采深度以每年8～12m的速度增加，可以预计在未来几年我国部分煤矿将进入1000m左右的深部开采。在进入深部开采以后，瓦斯治理将面临的关键问题主要有以下两个：（1）随着采深的增加，地应力增大，瓦斯压力迅速增加，致使煤与瓦斯突出矿井数量增多，在深部高应力作用下，煤岩体中积聚了大量的瓦斯气体能量和弹性应变能，受工程扰动的影响，煤体内的高压瓦斯气体和应变能急剧释放，导致煤岩结构瞬时破坏而产生煤与瓦斯突出。（2）由于地应力的增高，使得深部煤层开采面临的冲击地压频次和强度均有所增加。那么，如何解决深部开采条件下煤体的透气性和应力集中成为瓦斯治理的首要问题。矿井中浅部开采过程中，采用深孔预裂控制爆破技术进行煤与瓦斯突出及冲击地压的防治已取得了非常好的效果；同时，《煤矿井下深孔控制预裂爆破技术条件（MT1036-2007）》规范2007年已经发布，但根据中浅部埋深情况下，得出的爆破孔与控制孔的相关参数在矿井深部开采条件下是否能够有很好的适用性还有待通过实践来检验。采用理论分析、室内模型实验、数值模拟及现场工业试验相结合的方法，研究了深孔预裂控制爆破技术在矿井深部开采条件下，煤与瓦斯突出及冲击地压的防治方法。论文主要完成了以下工作：1.高应力低透气性煤层深孔预裂控制爆破增透的影响因素的确定通过对煤岩体爆破研究成果的总结分析，结合深部高应力低渗透煤层的赋存特点，确定了深部低渗透煤层深孔预裂控制爆破增透的影响因素为煤层地应力、煤层强度、煤层原始瓦斯压力、爆炸波和爆生气体的衰减规律等。2.高应力低透气性煤层深孔预裂控制爆破增透的理论分析综合应力波理论、煤岩体力学、爆破理论、断裂损伤力学的理论分析，描述了爆炸波（包括爆炸冲击波和爆炸应力波）在层状煤岩体介质中的传播规律；分析了控制孔的导向致裂机制；考虑高应力低透气性煤层深孔预裂控制爆破增透的上述主要因素的影响，推导了与时间相关的煤体深孔爆破裂纹尖端应力强度因子的积分表达式，同时给出了煤体深孔爆破裂纹扩展长度的计算公式，为煤层深孔预裂控制爆破工艺孔间距的确定提供了理论基础。3.含瓦斯煤体的深孔预裂控制爆破室内相似材料模型实验研究通过室内相似材料模型实验，系统地研究了地应力、瓦斯压力、煤的硬度三个主要影响因素与裂隙扩展的关系；研究了煤体爆破中的孔径、孔间距等布孔参数对爆破致裂效果的影响；为现场进行深孔预裂控制爆破参数设计提供依据，也为深孔预裂控制爆破理论分析提供验证。4.高应力低透气性煤层深孔预裂控制爆破增透的数值模拟研究采用FLAC3D通用软件，数值分析了爆炸波和爆生气体对煤体深孔爆破增透效果的影响；综合理论分析、相似材料模型实验、数值模拟的结果，系统地分析了上述影响因素对高应力煤层深孔爆破增透效果的影响，揭示了高应力煤层深孔预裂控制爆破增透的机理；并通过对比分析，指出了常规浅孔采掘爆破破岩机理和煤体深孔预裂控制爆破增透机理的不同。5.高应力低透气性煤层深孔预裂控制爆破增透的现场工程应用完善了深孔预裂控制爆破工艺相关设备，包括封孔设备、装药被筒材料，并研制了适应深部开采条件下高应力低透气性煤层打钻成孔的专用钻头；对两个典型的低渗透煤层进行现场工业试验及工业试验结果的分析，评价了深孔预裂控制爆破技术在深部开采低透气性高瓦斯煤层防突、防冲的效果及适用性。更多还原

【Abstract】 Most of the coal seams in China are deeply buried which possessdistinctive features, such as abundant gas content with high pressure, weakstiffness, low permeability and so on. Along with the increasing energydemand and the decreasing coal reserves in shallow depth, it is undoubtly thedeep buried coal will be mined in the near future years. For the mining depthincreasing at8-12m/year, most of the coal mines will be mined at more than1000m depth during few years in our country. There are two main seriourspartential problems in deep mining which influence the safety production ofcoal mining. One is the gas outburst. Because the geostress and coal seam gaspressure are increasing with the buried depth, the strength and frequency of theoutbursts are extremely higher compared with the coal seam buried at shallowdepth. Another one is coal outburst. Therefore, the improvement of coal seampermeability is the key point to prevent outburst in mining deeply buried coalseam with low permeability and high gas pressure.The long-hole pre-splitting controlled blasting technology was presentedseveral years ago to enhance the permeability of low permeable coal seam andmeanwhile its criterion was also published in2007. Although the betterapplicability of the blasting method was gained in enhancing the coal seampermeability buried at medium depth and shallow depth, it is still deserve tostudy its effectiveness in improving the permeability of deeply buried coalseam. On the basis of previous research results, the mechanism andapplicability of long-hole pre-splitting controlled blasting method in enhancingpermeability of low permeable coal seam buried at depth are deeply studied bytheoretical analysis, laboratory model test, numerical simulation and practicalapplication.Main research works invlud as following:1、Analyzing the related influenced factors on improving the permeabilityof high stressed and low permeable coal seam buried at depth by long-holepre-splitting controlled blasting method.The related influenced factors are determined by analyzing the researchresults of former studies and considering the features of high stressed coalseam buried at depth. The related factors include such as geostress, stiffness,gas pressure of coal seam and the attenuation of blasting wave and explosiongas in coal seam.2、Theoretical study on the mechanism of enhancing permeability of highstressed coal seam using long-hole pre-splitting controlled blasting method.Base on the theoretical analysis such as stress wave theory, coal and rockmechanics, blasting theory, fracture and damage theory, firstly, the blastingwave attenuation in layered coal seam was studied; then, the crack guiding role of control hole is analyzed; finally, an time related integration formula wasderived to calculate the blasting induced crack length. Not only all the affectedfacors described above are considered, the attenuation of blasting wave in coalseam was also considered in presented integral equation. The formula could beused to compute the distance between blast hole and control hole in practicalengineering.3、Laboratory model test of long-hole pre-splitting controlled blasting inimproving permeability of high stressed coal seam containing high pressuregas.Laboratory model test on enhancement the permeability of low permeablecoal seam by the blasting method was conducted. The relationship betweenblasting induced fracture length and related factors described above are gainedthrough laboratory model test. The research results not only provide referencefor practical design, but also could be an envidence to the theoretical analysis.4、Numerical simulation study on the mechanism and effectiveness ofenhancing permeability of high stressed low permeable coal seam containinghigh pressure gas buried at depth by long-hole pre-splitting controlled blastingmethod.Firstly, the effectiveness of blasting wave and explosion gas on theimprovement of permeability of high stress low permeable coal seam werequatitatively studied respectively, by comparing the crack length sepatatelyinduced by them. Then, the permeablility improvement influenced by therelated factors presented above was studied by considering therotical analysis,labarotory test and numerical simulation results together. After that, theenhancing permeability mechanism of long-hole pre-splitting controlledblasting method was revealed. Finally, the difference of mechanism betweenlong-hole blasting and shallow blasting was presented by comparing thebehavior of blasting wave and explosion gas during the two blastingprocedures.5、Practical engineering application of long-hole pre-splitting controlledblast in improvement the permeability of high stressed coal seam buried atdepth.The long-hole pre-splitting controlled blasting techonology was improved.It included hole-sealing equipment and charging cylinder. A new drilling headwas also developed adapting to the deep coal mining. Two practical deepburied coal seam projects illustrated that the long-hole pre-splitting controlledblasting technology could be used to enhance the permeability of lowpermeable coal seam in deep coal mining and desirable effectiveness could beexpected.更多还原