The idea and project of the “Medium－Scale Experiment Field for Earthquake Prediction”──Research on observations and applications of mining earthquake in Mentougou Coal Mine

A brief account of the development of the research on mining earthquakes and the general situation of the Mentougou Coal Mine medium scale experiment field for earthquake prediction and the project of monitor and prediction is given. The differences of waveforms between mining earthquakes and natural earthquakes is discussed. The magnitude frequency distribution of the 79 000 mining earthquakes of over M L1.0 from 1984 to 1995 is summarized . Finally, taking PH and PV, the principal compressive stress components of the focal mechanism of the mining earthquakes, as the criteria, analyses the stress background of the 12 large mining earthquakes.

Simulation of Paleotectonic Stress Fields and Distribution Prediction of Tectonic Fractures at the Hudi Coal Mine, Qinshui Basin

Study on tectonic fractures based on the inversion of tectonic stress fields is an effective method. In this study, a geological model was set up based on geological data from the Hudi Coal Mine, Qinshui Basin, a mechanical model was established under the condition of rock mechanics and geostress, and the finite element method was used to simulate the paleotectonic stress field. Based on the Griffith and Mohr-Coulomb criterion, the distribution of tectonic fractures in the Shanxi Formation during the Indosinian, Yanshanian, and Himalayan period can be predicted with the index of comprehensive rupture rate. The results show that the acting force of the Pacific Plate and the India Plate to the North China Plate formed the direction of principal stress is N-S, NW - SE, and NE - SW, respectively, in different periods in the study area. Changes in the direction and strength of the acting force led to the regional gradients of tectonic stress magnitude, which resulted in an asymmetrical distribution state of the stress conditions in different periods. It is suggested that the low-stress areas are mainly located in the fault zones and extend along the direction of the fault zones. Furthermore, the high-stress areas are located in the junction of fold belts and the binding site of multiple folds. The development of tectonic fractures was affected by the distribution of stress intensity and the tectonic position of folds and faults, which resulted in some developed areas with level I and II. There are obvious differences in the development of tectonic fractures in the fold and fault zones and the anticline and syncline structure at the same fold zones. The tectonic fractures of the Shanxi Formation during the Himalayan period are more developed than those during the Indosinian and Yanshanian period due to the superposition of the late tectonic movement to the early tectonic movement and the differences in the magnitude and direction of stress intensity.

Method for prevention and control of spontaneous combustion of coal seam and its application in mining field

Spontaneous combustion of coal seam has been and continues to be a big problem in coal mines. It could pose great threat to the safety of the whole mine and all miners, especially when it occurs in or nearby coal mines. Besides, environment of area surrounded mines during combustion can be threatened where large amount of toxic gases including CO_2, CO, SO_2 and H_2S can be leased by fire in mine. Hence, it is important and significant for scholars to study the controlling and preventing of the coal seam fire. In this paper, the complicated reasons for the occurrence and development of spontaneous combustion in coal seam are analysed and different models under various air leakage situations are built as well. Based on the model and approximately calculation, the difficulty of fire extinguishment in coal seam is pointed out as the difficulty and poor effect to remove the large amount of heat released. Detailed measurements about backfilling and case analyses are also provided on the basis of the recent ten years' practice of controlling spontaneous combustion in coal seams in China. A technical fire prevention and control method has been concluded as five steps including detection, prevention, sealing, injection and pressure adjustment. However, various backfill materials require different application and environmental factors, so in this paper, analyses and discussion about the effect and engineering application of prevention of spontaneous combustion are provided according to different backfilling technologies and methods. Once the aforementioned fire prevention can be widely applied and regulated in mines, green mining will be achievable concerning mine fire prevention and control.

Numerical simulation of spatial distributions of mining-induced stress and fracture fields for three coal mining layouts

In this study, the spatial distributions of stress and fracture fields for three typical underground coal mining layouts, Le, non-pillar mining （NM）, top-coal caving mining （TCM） and protective coal-seam mining （PCM）, are modeled using discrete element software UDEC, The numerical results show that different mining layouts can lead to different mining-induced stress fields, resulting in diverse fracture fields, For the PCM, the mining influenced area in front of the mining faces is the largest, and the stress concentration factor in front of the mining faces is the lowest, The spatial shapes of the mining-induced fracture fields under NM, TCM and PCM differ, and they are characterized by trapezoidal, triangular and tower shapes, respectively, The fractal dimensions of mining-induced fractures of the three mining layouts decrease in the order of PCM, TCM and NM, It is also shown that the PCM can result in a better gas control effect in coal mines with high outburst potential, The numerical results are expected to provide a basis for understanding of mining-induced gas seepage fields and provide a reference for high- efficiency coal mining,

Surrounding Rock Failure Mechanism and Control Technology of Gob-Side Entry with Triangle Coal Pillar at Island Longwall Panel in 15 m Extra-Thick Coal Seams

Taking the return air roadway of Tashan 8204 isolated island working face as the background, the evolution law of the stress field in the surrounding rock of the widened coal pillar area roadway during the mining period of the isolated island working face is obtained through numerical simulation. The hazardous area of strong mine pressure under different coal pillar widths is determined. Through simulation, it is known that when the width of the coal pillar is less than 20 m, there is large bearing capacity on the coal side of the roadway entity. The force on the side of the coal pillar is relatively small. When the width of the coal pillar ranges from 25 m to 45 m, the vertical stress on the roadway and surrounding areas is relatively high. Pressure relief measures need to be taken during mining to reduce surrounding rock stress. When the width of the coal pillar is greater than 45 m, the peak stress of the coal pillar is located in the deep part of the surrounding rock, but it still has a certain impact on the roadway. It is necessary to take pressure relief measures to transfer the stress to a deeper depth to ensure the stability of the triangular coal pillar during the safe mining period of the working face. This provides guidance for ensuring the stability of the triangular coal pillar during the safe mining period of the working face.

煤矿矿井水水质形成及演化的水动力场-水化学场-微生物场耦合作用与数值模拟

煤矿矿井水的水质形成与演化过程机理复杂,受水动力场、水化学场和微生物场等多场作用影响显著。深入研究并揭示煤矿矿井水水质形成机理与演化趋势、阐明采空区封闭后矿井水的多场耦合作用机制是矿井水污染防控与修复的理论基础。以鄂尔多斯盆地某煤矿采空区为水文地质原型,在前期研究的基础上,进一步建立了煤矿采空区积水水位回升、蓄满后水动力-水化学-微生物场(HCB)多场耦合室内相似模拟和数值模型。采空区水动力场研究结果表明基质-裂隙双孔隙模型能有效模拟采空区水位回升过程,模拟误差为9.9%,其模拟精度远高于理论预测和单孔隙模型。水化学场模拟结果与试验较为吻合,SO_(4)^(2-)、HCO_(3)-和p H模拟相对误差分别为3.0%、21.0%和6.2%,模拟结果较为可靠。模拟结果显示采空区蓄水过程中水岩反应和微生物作用不明显;而蓄满后水动力几乎停滞,但水化学场和微生物场较为活跃,2号煤和3号煤层中黄铁矿的氧化反应使得SO_(4)^(2-)质量浓度提升约24.6%;后期采空区水环境演化为弱酸性、厌氧还原条件,微生物降解作用凸显,将SO_(4)^(2-)有一定的“自净”能力。通过调整微生物代谢速率常数,可将SO_(4)^(2-)降解比例提高到61.6%。实际工程场景中可通过补充碳源、人工建立密闭厌氧环境等强化手段实现这一目标。将多场耦合室内试验和数值模拟技术拓展到煤矿采空区积水水质形成与演化规律研究,研究结论可为煤矿区矿井水污染防治提供指导。

Behaviors of overlying strata in extra-thick coal seams using top-coalcaving method

Accidents such as support failure and excessive deformation of roadways due to drastic changes in strata behaviors are frequently reported when mining the extra-thick coal seams Nos.3e5 in Datong coal mine with top-coal caving method,which significantly hampers the mine's normal production.To understand the mechanism of strata failure,this paper presented a structure evolution model with respect to strata behaviors.Then the behaviors of strata overlying the extra-thick coal seams were studied with the combined method of theoretical analysis,physical simulation,and field measurement.The results show that the key strata,which are usually thick-hard strata,play an important role in overlying movement and may influence the mining-induced strata behaviors in the working face using top-coal caving method.The structural model of far-field key strata presents a 'masonry beam' type structure when'horizontal O-X' breakage type happens.The rotational motion of the block imposed radial compressive stress on the surrounding rock mass of the roadway.This can induce excessive deformation of roadway near the goaf.Besides,this paper proposed a pre-control technology for the hard roof based on fracture holes and underground roof pre-splitting.It could effectively reduce stress concentration and release the accumulated energy of the strata,when mining underground coal resources with top-coal caving method.

基于改进人工势场算法的煤矿井下机器人路径规划

路径规划是煤矿机器人在煤矿井下狭小巷道空间中应用亟待解决的关键技术之一。针对传统人工势场(APF)算法在狭小巷道环境中规划出的路径可能离巷道边界过近,以及在障碍物附近易出现目标不可达和路径振荡等问题,提出了一种基于改进APF算法的煤矿机器人路径规划方法。参考《煤矿安全规程》有关规定建立了巷道两帮边界势场,将机器人行驶路径尽量规划在巷道中间,以提高机器人行驶安全性;在障碍物斥力势场中引入调节因子,以解决目标不可达问题;引入转角限制系数以平滑规划出的路径,减少振荡,提高规划效率,保证规划路径的安全性。仿真结果表明:当目标点离障碍物很近时,改进APF算法可成功规划出能够抵达目标点的路径;改进APF算法规划周期数较传统算法平均减少了14.48%,转向角度变化累计值平均减少了87.41%,曲率绝对值之和平均减少了78.09%,表明改进APF算法规划的路径更加平滑,路径长度更短,规划效率和安全性更高。

综放架后膏体充填空间实测与顶煤冒放性影响规律研究

针对综合机械化放顶煤开采中的矸石处置问题,提出了一种放顶煤架后膏体充填方法,设计了柳巷煤矿综放工作面采空区空洞现场监测方案,定性分析了5个方面对顶煤冒放性的影响,采用PFC^(2D)数值模拟方法,定量分析了充填高度对顶煤冒放性的影响。研究结果表明:倾向方向上工作面上部端头附近采空区空洞体积最大,走向方向上工作面刚推进到新位置时采空区空洞体积最大,支架顶梁后方空洞体积大于支架尾梁上方;充填高度从0增加至3 m时,顶煤放出率由92.56%降低至86.11%,降低了6.45个百分点,顶煤含矸率由13.94%降低至13.17%,降低了0.77个百分点,相比于顶煤含矸率,充填高度对顶煤放出率影响较大。研究可为类似地质条件综放架后膏体充填开采实现提供理论基础。

基于知识图谱的煤矿建设安全领域知识管理研究

为解决煤矿建设过程中数据积累存在的知识冗余现象,研究基于知识图谱(KG)的安全领域知识管理。从安全管理系统结构和安全隐患风险管理2个维度,系统化分析领域标准规范文本,界定煤矿建设安全管理领域的12类实体类型和10种关系类型,完善知识结构模式;选取领域43部标准规范为数据源,引入规则、机器学习法、深度学习法识别文本实体和关系;针对不同实体类型,提出领域知识综合方法框架,并对比分析双向长短期记忆(BiLSTM)和条件随机场(CRF)与双向编码器表示(BERT)-BiLSTM-CRF模型。研究结果表明:BERT-BiLSTM-CRF模型在准确率、召回率和F1值方面均比BiLSTM-CRF模型高出7%,验证了所选模型的优越性和准确性;通过知识抽取、知识存储及可视化等过程,挖掘出煤矿建设安全领域不同实体类型所包含的实体和不同实体间的关系。

深部矿井高温采煤工作面热源及温度场演化规律分析

深部矿井开采面临严重的热害问题,其成因复杂且防治难度大。研究高温采煤工作面热源及温度场演化规律对深部矿井热害防治具有重要意义。以平煤股份十矿为工程背景,对己_(17)-24090采煤工作面风流热力参数进行现场调研,分析了工作面热源及其对井下温升的贡献度,并进一步建立采煤工作面温度场数值模型,明确了采煤工作面温度场演化规律。研究结果显示,引起井下温升的主要热源是围岩散热和机电设备散热,散热量分别占总热源散热量的28.2%和20.6%;地表大气对己_(17)-24090采煤工作面的温度场影响不大,风流在到达工作面之前已经趋于热力学稳定状态;在同一通风时间下,距离机巷口越远,温度越高;在距离相同时,随着通风时间的增加,温度上升幅度有所减缓。研究成果可为深部矿井热害治理工作及降温工程设计提供参考和理论依据。

特厚煤层工作面煤厚变化电磁波透视响应特征

目的为掌握煤厚变化对特厚煤层工作面电磁波透视探测的影响,以准确圈定地质异常区,保障工作面安全高效生产。方法根据煤层工作面地质条件,利用三维仿真软件,对煤厚变化进行了电磁波透视数值模拟,并结合工作面探查实例进行了分析。结果0~20m煤厚范围,随煤厚减小,电磁波透视场强值呈抛物线下降趋势,可分为缓慢降低(煤厚≥9m)、明显降低(9m>煤厚≥5m)和快速降低(煤厚<5m)3个范围。煤厚10m以上的工作面适合于依据相对煤层变薄程度和变薄区煤厚来分析透视电磁波响应:变薄程度>1/3正常煤厚且煤厚<8m的薄煤区有明显响应,变薄区煤厚越小,透视电磁波场强降低越显著。煤厚10m以下的工作面,可以仅依据相对煤层变薄程度分析透视电磁波响应:变薄程度>1/4正常煤厚的薄煤区有明显响应,变薄程度越大,透视电磁波场强降低越显著。陕西金源招贤矿业有限公司特厚煤层1304工作面探测实例表明:正常煤厚变化及薄煤区的电磁波响应特征与数值模拟结果一致;工作面物探圈定的落差1m以上断层及薄煤区范围,与实际揭露范围相吻合。结论利用煤厚变化电磁波响应特征能够可靠地探查特厚煤层工作面地质异常区范围。

弱胶结巨厚砂砾岩含水层离层突水机制研究

安新煤田主采煤层上覆巨厚弱胶结砂砾岩含水层,富水性弱,但多个工作面回采期间发生突水,查明突水机制是矿井水害防治的关键。通过水文地质特征分析,阐明了砂砾岩含水层厚度分布特征和富水性分区特征。采用岩石单轴抗压强度、三轴声发射、X衍射试验等方法,获得了顶板隔水层岩石物理力学性质。基于关键层理论分析、导水裂隙带与采动富水异常区层位关系及相似模拟试验成果,建立了4种条件下巨厚砂砾岩含水层突水的水文地质结构模型,揭示了砂砾岩含水层不同条件下的突水机制,并明确了研究区突水点的突水机制,提出了隔水保护层失稳导致突水的工程判据。研究结果表明:研究区东部局部区域含水层富水性中等,以往多次突水均发生在弱富水区;砂砾岩含水层下顶板泥岩中黏土矿物含量达到59.6%,亲水性强,具有良好的隔水作用;但在采动作用下顶板隔水层岩体卸压后强度降低,厚度较薄时,受上部岩层载荷和采动富水区静水压力作用易发生破坏,成为良好导水通道;砂砾岩含水层物理力学性质特殊,采动扰动后孔隙裂隙发育,形成了富水变化异常区;弱胶结砂砾岩突水的强度与下部基岩特征、导水裂隙带发育高度、隔水保护层厚度等因素相关;研究区弱胶结砂砾岩发生突水的工程判据为正常区隔水保护层厚度小于30 m,受背斜构造影响区隔水保护层厚度小于60 m。弱胶结巨厚砂砾岩含水层离层突水机制及工程判据对西部矿区水害防治提供了借鉴。

矿震诱发高应力巷道厚顶煤动力失稳机制

【目的】厚煤层沿底掘进煤巷普遍存在厚顶煤,工作面矿震对巷道厚顶煤产生动载作用,易诱发厚顶煤动力失稳和冒顶-冲击复合灾害,亟需探究矿震动载作用下巷道厚顶煤动力失稳机制。【方法】以陕西彬长矿区深部厚顶煤巷道为工程背景,调研分析深部高应力巷道厚顶煤动力失稳特征,数值模拟研究不同静动载作用下巷道厚顶煤多场演化规律,提出矿震诱发高应力巷道厚顶煤动力失稳机制。【结果和结论】结果表明,巷道厚顶煤冒顶区域距回采工作面较远,冒顶后裸露平整顶板,顶板锚索拉断,冒顶区域附近均发生大能量矿震,呈现冒顶-冲击复合灾害现象。随静载增加,巷道围岩裂隙发育深度及变形不断增加;随动载作用时间和动载强度增大,顶煤震动速度、加速度及裂隙发育程度不断增大,顶煤离层量显著增加;顶板锚杆索均位于顶煤裂隙发育区,支护性能大幅降低。静动载作用下巷道厚顶煤累积损伤及离层量不断增大,大能量矿震动载使浅部破碎顶煤震动速度及加速度显著增大,作用在锚索上载荷超过其承载能力,锚索被拉断,浅部破碎煤体以较高速度冒落,诱发厚顶煤动力失稳和冒顶-冲击复合灾害。在此基础上,提出了采用重建厚顶煤主被动支护和加强卸压的深部巷道厚顶煤动力失稳灾害的防治方法。

TBM掘进煤矿深井巷道支护方案优化实践

针对煤矿深井巷道TBM掘进施工中围岩支护方案少有规范可供参考,支护施工须同时兼顾支护强度和支护施工速度等问题,根据煤矿深部地层岩层物理力学性质和地应力场参数等工程地质条件,开展TBM掘进巷道数值模拟,获得不同支护方案下围岩应力场、位移场演化规律,优选合理支护方案,并在TBM掘进煤矿深井巷道工程实践中应用。工程现场监测数据表明,巷道开挖后第70天,顶板下沉量和两帮收敛量停止增加,锚杆轴力停止增长,所采用的支护方案满足巷道围岩稳定性控制的需要。

煤矿低浓度瓦斯热氧化中蜂窝陶瓷燃烧流场数值计算

为研究煤矿低浓度瓦斯在蜂窝陶瓷燃烧流场内流动、燃烧、传热反应,借助数值模拟手段,建立了包含周期性条件、甲烷燃烧机理、湍流-层流流动特性的矩形微通道模型,通过对其变参数分析,解析预混气体流速、甲烷体积分数和预混气预热温度变化对蜂窝陶瓷燃烧流场的影响。结果表明:预混气体流速主要影响燃烧流场内的火焰面传播速度和最高火焰温度,速度越大,火焰面前沿的温度梯度越大;甲烷体积分数的降低导致火焰面位置明显后移,火焰面处峰值与化学反应速率明显下降,流场内的温度下降;预混气进气温度提高时,火焰的峰值温度上升,化学反应速率增大。

东峰煤矿井田支护措施探究

受复杂地质水文因素影响,煤矿企业在开展采煤掘进作业过程中可能会面临一些安全隐患问题,因此需要做好前期的支护设计,严格按照地质、水文等数据信息来进行综合分析,从而选择合适的支护技术及方式。立足东峰煤矿井田实际情况,从了解其地形、地貌、水系、气象、地震等多方面因素入手,围绕运输顺槽、进风顺槽及沿空留巷角度,探讨支护措施,致力于更好地发挥支护技术及工艺的优势,保障煤矿企业安全稳定运行。

煤矿综掘面用风机流场特性研究与性能试验

针对煤矿综掘面采用的对旋轴流风机流场特性复杂、风机流量波动较大、易造成煤矿井下通风不畅等问题,研究煤矿综掘面风机流场特性,基于风机特点建立风机数学模型,采用数值模拟分析法在Fluent中搭建风机流场物理模型设定仿真时间和参数进行模拟。结果表明,风机全压与风机转速成正相关,随风机转速的增大而增大,风机的叶顶间隙越大,风机效率越低,风机的效率随流量的不断增大呈先增大后减小的趋势,且当流量为750m^(3)/min时达到最大值,试验效率为0.78。为保证最高的运转效率,可选择最优的流量匹配,为后期实现风机高效率运行提供理论参考。

煤系气合采井排采工作制度研究与应用——以五里堠井田为例

制定煤系气合采井排采全生命周期的合理排采工作制度能为气井高产提供重要保障。以五里堠井田3#+4#煤层、夹层砂泥岩、15#煤层为产气层,基于生产特征划分了排采阶段,制定了不同排采阶段的排采工作制度和核心目标,现场排采产气效果良好。该研究成果为煤系气合采井全生命周期排采工作提供了借鉴。

综合地质勘探方法在煤矿地质勘探领域的运用研究

针对煤矿地质勘探领域,探讨了综合地质勘探方法的运用及其研究的意义,介绍了传统地质勘探方法的局限性,包括单一数据源、信息获取有限的问题,详细阐述了综合地质勘探方法的理论基础和技术特点。该研究成果对于促进煤矿地质勘探技术的创新和提升具有一定的理论和实践价值。