瓦斯地质历史分析的基本思想与实践

煤与瓦斯突出倾向与煤层的变质变形历史有关。煤层的变质变形演化大致有３种基本模式：变质一变形模式；同变形变质模式：变形－变质模式。具有第１种演比模式的煤层突出危险性较小，而具有第２、３种模式的煤层突出程度较高。     

福建长乐—南澳变质带演化的PTtd轨迹

长乐－南澳变质带变质矿物的共生组合，主要变质矿物角闪石、长石、石榴子石的成分和环带以及变形构造等的研制表明，该带遭受了３期变形变质作用，每一期变形均有对应的变质作用。变质作用的温压条件、构造变形时间分别是：５２５－５８０℃，０。４７－０．５８ＧＰａ，１６５Ｍａ；４５０－５５０℃，０．２－０．５ＧＰａ，１２０Ｍａ；１７０－３５０℃，０．１－０．２ＧＰａ，９０Ｍａ。变质带演化的ＰＴｔｄ轨迹为逆时针方向     

北京周口店地区晚古生代煤系煤层变质变形机制研究

北京周口店地区晚古生代煤系煤层遭受过强烈的变质与变形。与华北同时期煤田相比，它独具特色：煤级达高级无烟煤，乃至接近于超无烟煤，煤层的糜棱化构造煤极其发育。作者采用薄片、扫描电镜及Ｘ衍射诸手段对煤系及煤层的变质变形特征进行了系统的研究，确定了煤变质作用发生的时间，变质作用类型和变质作用温压条件；同时探讨了煤层变形，即糜棱化作用发生时期及形成条件。     

艾维尔沟矿区瓦斯地质规律研究

运用瓦斯地质理论,结合地质勘探和矿井生产揭露的瓦斯地质资料,研究了艾维尔沟矿区的瓦斯地质规律.综合分析了地质构造、煤层埋深、构造演化、煤变质程度等对煤层瓦斯赋存的影响.提出了煤层埋深是艾维尔沟矿区煤层瓦斯赋存区域的主控因素,同时受构造演化、煤变质程度等因素影响,在局部区域受地质构造因素控制明显.因各种因素的共同作用,在沿煤层走向上,同一水平标高,矿区西部瓦斯含量最高,东部次之,中部最小;沿煤层倾向方向上,瓦斯含量具有随煤层埋深的增加而增大的整体趋势.在向斜构造轴部及断层带附近瓦斯富集.     

高瓦斯特厚煤层煤与卸压瓦斯共采原理及实践

论述了高瓦斯低透气性有煤与瓦斯突出危险特厚煤层和上覆采动断裂带有高瓦斯涌出的特厚煤层两种煤与瓦斯高产高效卸压共采模式、原理及其实践所取得的丰硕成果。阐明了现场考察得出的煤层采动引起远程上覆煤层卸压变形规律与卸压瓦斯抽采规律。     

抑制突出的增压揭煤法研究

根据突出机理的球壳失稳假说给出的３个力学条件,提出了一种新的抑制突出的方法－增压揭煤法。通过１０次增压揭煤试验及相应的对比试验,证明在增压揭煤的条件下可以显著地抑制煤层的突出危险性,为煤矿现场提供了一种快速、安全的防治突出的方法。     

平顶山十矿煤与瓦斯突出地质因素分析

随着矿井开采深度的增加，煤与瓦斯突出已愈来愈成为影响和制约生产的重要因素,为确保煤矿安全生产，作者对平项山十矿影响突,出煤层瓦斯赋存和突出的地质构造、煤层厚度的变化、煤体结构、埋藏深度等地质因素进行了分析研究，认为：地质条件对煤层瓦斯体积含量和煤与瓦斯突出的分区分带具有明显的控制作用；井田内厚度小于2m的单一煤层一般不具突出危险性，但随着开采深度的增加有可能发生突出；戊9-10煤层分又合并线附近为煤与瓦斯突出带，其他煤层分又合并线附近可能形成煤与瓦斯突出危险带.     

中国鲁东造山带前寒武纪构造变形及其演化

中国鲁东造山带前寒武记构造变形可以划分出三个变形旋回与五个变形幕,即吕梁变形旋回第一变形幕,四堡变形旋回第二变形幕,以及晋宁变形旋回第三、四、五变形幕。前三幕表现为强塑性流动变形作用,而第四、五幕则分别属于较强塑性及中强塑性变形作用,这五个变形幕总的均以塑性变形作用为突出特征,说明它们的变形环境之间虽有变化,但不明显,只是变形机制和应力场型式有一定变化。第一变形幕导致麻粒岩相区域变质作用,并且产生区内最早的变形叶理,为尔后的构造变形奠定了基础。第二、三变形幕体现了碰撞带形成机制及过程,与超高压-高压变质杂岩、中酸性侵入杂岩及角闪岩相区域变质作用等关系密切,因此在区内前寒武纪地质演化中居于主导地位。第四、五变形幕反映碰撞带形成之后演化特征,控制了现今区域大地构造构造构格的形成。     

精查勘探期间井田煤与瓦斯突出危险性预测

本文通过精查勘探期间测定煤层瓦斯压力、瓦斯含量、瓦斯突出指标及瓦斯地质条件的分析，对韩庄井田３号、１５号煤层突出危险性进行了预测，并为生产设计部门提供了科学依据．     

巨厚火成岩对煤层瓦斯赋存及突出灾害的影响

通过采用火成岩取芯化验、煤样测试及现场观测等方法,分析了海孜煤矿10煤层覆岩中巨厚火成岩的力学性能,探讨了巨厚火成岩对远程10煤层瓦斯赋存与突出灾害的影响.结果表明:10煤层受巨厚火成岩的高温烘烤作用,煤体变质程度增高,煤层瓦斯吸附量增大,极限吸附量达到31.6753 m3/t;同时,巨厚火成岩均厚达120 m,单轴抗压强度平均为144.21 MPa,为矿井的主关键层,其阻碍了煤层瓦斯逸散,使煤层瓦斯含量高,且由于巨厚火成岩长期保持不断裂,导致10煤层工作面两端应力集中影响范围大大增加,达到100 m左右,更易具备煤与瓦斯突出的必要条件.     

二道岭矿区地质构造的控气规律研究

针对内蒙古二道岭矿区构造复杂,构造部位及影响带多显示瓦斯异常和煤与瓦斯突(喷)出多发、易发等特点,应用瓦斯地质理论,重点研究构造对煤层瓦斯赋存和突(喷)出的控制作用及规律。研究表明,"封闭型"压性、压扭性构造为煤层瓦斯的保存提供了良好的"封存效应",是控制区内煤层瓦斯含量整体较高和不均衡分布的关键因素;构造类型、性质和组合方式共同控制着煤层瓦斯的分区、分带和煤与瓦斯突(喷)出范围及机率。     

Investigations into the identification and control of outburst risk in Australian underground coal mines

Australian coal mines currently use gas content to assess outburst risk. The gas content threshold values for each mine are indirectly determined from measurement of gas volume liberated from 150 g coal samples during Q_3 residual gas content testing. It has been more than twenty years since this method, known as desorption rate index(DRI), was presented to the Australian coal industry, and in that time, there have been significant changes in mining conditions and the outburst threshold limits used at the benchmark Bulli seam mines. NSW Regulations list matters to be considered in developing control measures to manage the risk of gas outburst, and specifies that gas content, or DRI method, is used as the basis for determining outburst control zone. Whilst Queensland Regulations state that a coal or rock outburst is a high potential incident, there is no guidance provided to assist mine operators to define outburst prone conditions. A research project is planned at UOW to investigate the application of the DRI method and other potentially significant factors, such as gas pressure, coal toughness and permeability, which can be utilised by mine operators to assess outburst risk and determine appropriate outburst threshold limits and controls.     

煤和瓦斯突出机理的流变假说

目前煤和瓦斯突出机理的假说,都是在弹性力学基础上建立的,缺少时间因素,难于完满地解释突出的发生发展过程。作者通过对含瓦斯煤样在三维受力状态下流变特性的研究,得出了含瓦斯煤样蠕变行为的数学模型,能够比较好地阐明突出的机理。实验表明,突出煤和非突出煤其流变行为并无本质区别,只要条件具备,各类煤层都有产生突出的可能。含瓦斯煤蠕变方程的导出为建立广义的突出危险综合指标提供了基础。     

Coal and rock fissure evolution and distribution characteristics of multi-seam mining

Henan Pingdingshan No.10 mine is prone to both coal and gas outbursts. The E_9–10 coal seam is the main coal-producing seam but has poor quality ventilation, thus making it relatively difficult for gas extraction. The F₁₅ coal seam, at its lower section, is not prone to coal and gas outbursts. The average seam separation distance of 150 m is greater than the upper limit for underside protective seam mining. Based on borehole imaging technology for field exploration of coal and rock fracture characteristics and discrete element numerical simulation, we have studied the evolution laws and distribution characteristics of the coal and rock fissure field between these two coal seams. By analysis of the influential effect of group F coal mining on the E_9–10 coal seam, we have shown that a number of small fissures also develop in the area some 150 m above the overlying strata. The width and number of the fissures also increase with the extent of mining activity. Most of the fissures develop at a low angle or even parallel to the strata. The results show that the mining of the F₁₅ coal seam has the effect of improving the permeability of the E_9–10 coal seam.     

大采高综采工作面瓦斯与煤自燃综合治理技术

针对张集煤矿1215（3）高产高效综采工作面高瓦斯、易自燃开采过程中的安全问题,本文介绍了大采高综采工作面采空区顶板高位抽采技术,优化顶板走向钻孔位置,结合顺层钻孔和上隅角埋管等抽采瓦斯措施综合治理瓦斯,同时采取均压通风、加快工作面推进速度、采空区灌浆、注氮等技术措施防治煤自燃,保证了回采期间回风流瓦斯浓度平均小于0.5%,CO浓度20PPm以下,实现了工作面的正常安全生产。研究成果为淮南矿区一次采全高高产高效工作面的瓦斯、防火治理提供了借鉴经验。     

Theoretical analysis of influencing factors on resistance in the process of gas migration in coal seams

Inspired by previous resistance models for porous media, a resistance expression of gas migration within coal seams based on the ideal matchstick geometry, combined with the Darcy equation and the modified Poiseuille equation is proposed. The resistance to gas migration is generally dynamic because of the variations in adsorption swelling and matrix shrinkage. Due to the limitations of experimental conditions,only a theoretical expression of resistance to gas migration in coal is deduced, and the impacts of tortuosity, effective stress and pore pressure on the resistance are then considered. To validate the proposed expression, previous data from other researchers are adopted for the history matching exercise, and the agreement between the two is good.     

Dynamic development characteristics of amounts of gas and levels of pressure in the Pan-1 coal mine of Huainan

The Pan-1 coal mine located in Huainan municipality, Anhui province, is abundant in coal resources. In order to discover the natural conditions of gas in its coal seams, we inverted the burial history of these coal seams using the software of Easy%Ro method and simulated the development process of gas volumes and pressure of the major coal seams using CBMHistory Simulation Software. Our analysis shows that the devolution of gas volumes and levels of pressure can be divided into four stages: I.e., a biogas stage (P1-P3), a pyrolysis gas stage (T1-T2), an active gas enrichment stage (T3-K1) and a gas dissipating stage (K2-present). Cur-rently, the average amounts of gas and gas pressure in coal seams Nos. 13-1,11-2 and 8 of the Pan-1 coal mine are 8.18 m3/t and 2.20 Mpa; 3.89 m3/t and 2.47 Mpa and 6.35 m3/t and 2.89 Mpa, respectively. This agrees very well with current mining data.     

3D numerical simulation of boreholes for gas drainage based on the pore–fracture dual media

A gas migration controlling equation was formulated based on the characteristics of the dual pore–fracture media of coal mass and in consideration of the matrix exchange between pores and fractures.A model of permeability dynamic evolution was established by analyzing the variation in effective stress during gas drainage and the action mechanism of the effect of coal matrix desorption on porosity and fracture in the coal body.A coupling model can then be obtained to characterize gas compressibility and coal deformability under the gas–solid coupling of loading coal.In addition,a 3D model of boreholes was established and solved for gas drainage based on the relevant physical parameters of real mines.The comparison and analysis results for the law of gas migration and the evolution of coal body permeability around the boreholes before and after gas extraction between the dual media and the single-seepage field models can provide a theoretical basis for further research on the action mechanism of gas drainage.     

孔隙气体对煤体变形及蚀损作用机理

在前人实验及理论分析的基础上，对瓦斯在煤体中的赋存形态、含瓦斯煤的特殊力学现象及瓦斯对煤体的蚀损过程进行了解释和半定量分析，得出的结论与实验规律相吻合。     

Regional gas drainage techniques in Chinese coal mines

China’s rapid economic development has increased the demand for coal. These results in Chinese coal mines being extended to deeper levels. The eastern Chinese, more economical developed, regions have a long history of coal mining and many coal mines have now started deep mining at a depth from 800 to 1500 m. This increase in mining depth, geostresses, pressures, and gas content of the coal seam complicates geologic construction conditions. Lower permeability and softer coal contribute to increasing numbers of coal and gas outburst, and gas explosion, disasters. A search on effective methods of preventing gas disasters has been provided funds from the Chinese government since 1998. The National Engineering Research Center of Coal Gas Control and the Huainan and Huaibei Mining Group have conducted theoretical and experimental research on a regional gas extraction technology. The results included two important findings. First, grouped coal seams allow adoption of a method where a first, key protective layer is mined to protect upper and lower coal seams by increasing permeability from 400 to 3000 times. Desorption of gas and gas extraction in the protected coal seam of up to 60%, or more, may be achieved in this way. Second, a single seam may be protected by using a dense network of extraction boreholes consisting of cross and along-bed holes. Combined with this is increased use of water that increases extraction of coal seam gas by up to 50%. Engineering practice showed that regional gas drainage technology eliminates regional coal and gas outburst and also enables mining under low gas conditions. These research results have been adopted into the national safety codes of production technology. This paper systematically introduces the principles of the technology, the engineering methods and techniques, and the parameters of regional gas drainage. Engineering applications are discussed.