晋城矿区东部9号煤层及其顶底板岩性的研究

通过对9号煤层及其顶底板岩性的研究,得出如下结论9号煤层煤层厚度变化很大,但层位稳定,在现代开采技术条件下应属大部可采煤层;9号煤层顶板K4灰岩厚度不稳定、相变大,须注意小于0.5 m厚度顶板范围及相变部位的顶板管理;9号煤层底板为高岭石粘土岩,遇水易膨胀底鼓,对综采机械化生产可造成影响.     

“三软”极不稳定煤层综采技术研究

偃龙矿区开采的山西组二．煤层属于“三软”极不稳定煤层,其突出特征为煤层松软、厚度和倾角变化大,顶板及底板松软、破碎,赋存条件复杂,开采极其困难．嵩山煤矿以多项支护技术专利为支撑,采用底板岩巷的“一巷三用”,合理选择高强度轻型放顶煤支掩式液压支架,以及综采防片帮和防冒顶等技术,实施综采机械化开采,实现了“三软”煤层的安全高效开采,取得了显著效果．     

煤层气开采后成庄矿15号煤层底板突水危险性评价

研究煤层气开采后煤层底板突水机制及危险性评价,对于煤炭安全开采具有重要的理论和实际意义.从岩石力学和地质力学两方面对煤层气开采后煤层底板突水进行理论分析,并以山西晋煤集团成庄矿15号煤层底板奥陶系含水层为例,建立突水危险性评价模型.结果表明:煤层气开采后,若煤层底板与奥陶系含水层导通,煤层底板突水的主控因素按权重从大到小依次为底板最小主应力、底板含水层水压、有效隔水层厚度、地质构造;若煤层底板与奥陶系含水层未导通,底板突水控制因素按权重从大到小依次为底板含水层水压、有效隔水层厚度、含水层富水性、地质构造、岩石破裂压力和底板最小主应力;采用层次分析法确定主控因素权重,利用分形-脆弱性指数法进行突水危险性分区,即研究区西部脆弱性较强,中北部为过渡区,东南大部为安全区.该评价模型可为煤层气开采后煤层底板突水危险性评价提供参考.     

冯营矿矿井突水机理分析

针对冯营矿矿井水文地质条件复杂、水害严重的现状,研究了矿井充水水源、充水通道等充水条件,认为石炭系L8灰岩水、顶板砂岩空隙裂隙水和L2灰岩水是主要充水水源,断裂构造是主要的导水通道．研究表明：煤层顶板砂岩含水性相对较弱,太灰和奥灰含水层属中等-强富水性;断裂构造是沟通煤层底板太原组L8,L2灰岩和奥陶系（O2）灰岩的主要通道,也是矿井突水且突水量较大的主要因素之一．井田断层发育且导水良好,形成矿井突水的潜在威胁;对煤层底板采动裂隙影响的计算表明其有效隔水层较薄,加之矿压对底板的破坏,可构成煤层底板导水通道．以上因素导致冯营矿水害频发．     

冯营矿矿井突水机理分析

针对冯营矿矿井水文地质条件复杂、水害严重的现状,研究了矿井充水水源、充水通道等充水条件,认为石炭系L8灰岩水、顶板砂岩空隙裂隙水和L2灰岩水是主要充水水源,断裂构造是主要的导水通道．研究表明：煤层顶板砂岩含水性相对较弱,太灰和奥灰含水层属中等-强富水性;断裂构造是沟通煤层底板太原组L8,L2灰岩和奥陶系（O2）灰岩的主要通道,也是矿井突水且突水量较大的主要因素之一．井田断层发育且导水良好,形成矿井突水的潜在威胁;对煤层底板采动裂隙影响的计算表明其有效隔水层较薄,加之矿压对底板的破坏,可构成煤层底板导水通道．以上因素导致冯营矿水害频发．     

基于应力控制箱梁截面设计数值模拟分析

为了研究箱梁截面尺寸对箱梁力学行为的影响,分别以梁高、顶板、腹板及底板为参数,通过建立有限元模型,分析了各参数变化对箱梁应力变化的影响及敏感性.分析结果表明,随着顶板厚度的增大,箱梁顶板横向拉应力逐渐减小,箱梁顶板适宜厚度为24~36 cm;随着腹板厚度的增加,箱梁斜截面主拉应力逐渐减小,墩顶截面腹板的适宜厚度约为跨径的1/260~1/170,支座截面腹板的适宜厚度为墩顶截面腹板厚度的1/2.0~1/1.6;随着顶板厚度的增加,墩顶截面底板压应力也呈逐渐减小趋势,墩顶截面底板的适宜厚度约为跨径1/220~1/140,跨中截面底板的适宜厚度为20~31 cm.最后,建议在箱梁结构设计时,应通过整体分析、局部分析综合考虑各因素来确定其最优设计参数,以提高箱梁的承载能力和抗裂性能.     

基于板壳理论的隐伏陷落柱突水煤层底板破断机理研究

为揭示陷落柱突水时煤层底板的破断机理,基于板壳理论和断裂力学理论,建立隐伏陷落柱突水煤层底板的破断力学模型,研究陷落柱突水时煤层底板裂纹的扩展机理,得到底板内应力分布情况和裂纹应力强度因子。结果表明:横向荷载作用下,煤层底板内的应力与煤层底板厚度呈负相关,与距离中面的位置、半径和水压呈正相关;在含有裂纹的煤层底板中,随着底板厚度增加、裂纹增长和底板半径减小,裂纹越难扩展。利用理论结果分析淮南矿业(集团)有限责任公司张集煤矿"2·18"特大突水事故煤层底板破断机理,分析结果与现场实际情况相符。     

煤层顶板岩层厚度取值在含砂率计算中的应用

煤层顶板岩层含砂率是影响瓦斯质量体积的重要因素之一,本文利用相关分析和逐步逼近的方法,确定统计的煤层顶板厚度,提出了改进的含砂率表达方法--煤层顶板岩层效应厚度影响系数,从而实现了对煤层顶板岩层"含砂率"的准确计算.该研究方法可以在其它矿井中推广应用.     

顶板岩层对冲击矿压的影响规律研究

采用模拟试验方法研究了顶板岩层对煤体应力状态的影响,并根据震动能量对煤体的破坏效应和在岩体中的传播衰减规律,从能量角度分析了煤层上方不同厚度和强度的顶板岩层对煤体冲击的影响程度.结果表明,顶板释放的能量与岩层强度呈对数关系、与顶板厚度呈指数关系,坚硬、厚层顶板岩层会对煤体产生更为强烈的扰动,使冲击矿压危险性明显升高.另外,具有一定厚度和强度且距离煤层较近的老顶岩层运动产生的冲击载荷对煤体的影响作用较大.某矿一个工作面的冲击矿压防治工程实践表明,对该煤层上方的顶板岩层实施爆破弱化处理技术措施后,可有效降低工作面回采过程中的冲击危险性.     

登封煤田新登煤矿水文地质特征及瓦斯赋存规律

为了揭示登封煤田新登煤矿水文地质特征及瓦斯赋存规律,以便更好地为安全生产服务,基于煤层瓦斯运移、散失、赋存理论,结合矿井勘探和生产揭示的瓦斯地质资料,分析新登煤矿瓦斯赋存、分布规律.通过拟合煤层埋深、煤层厚度、直接顶板特征、底板灰岩水矿化度与煤层瓦斯含量的数值关系,结合太原组灰岩地下水动力场分布特征,划分水文地质单元,...     

Prediction of rock-burst-threatened areas in an island coal face and its prevention:A case study

The island coal face arises in coal mines with the purpose of preventing gas explosion or maintaining the balance between mining and tunneling. However, its particular stress conditions in the surrounding rock may increase the difficulty of stress control in the coal face and in its mining roadways, especially when the coal seam, the roof, and the floor have rock-burst propensities. The high energy accumulated in the island coal face and in its roof and floor will intensify rock-burst propensity or even induce rock burst,which further result in great casualties and financial losses. Taking island coal face 2321 in Jinqiao coal mine as a case, we propose a method for the prediction of rock-burst-threatened areas in an island coal face with weak rock-burst propensity. Based on the analysis of the movement of the overlying roof and characteristics of stress distribution, this method combined numerical simulation with drilling bits to ensure the prediction accuracy. The effects of coal pillars with different widths on the mitigation of stress concentration in the coal face and on the prevention of rock burst are analyzed together with the mechanism behind. Finally, corresponding measures against the rock burst in the island coal face are proposed.     

薄煤层开采对上覆构筑物基础变形影响的数值模拟研究

煤层开采过程中,在煤层顶、底板岩层一定的条件下,煤层的倾角和埋深对地表变形有很大的影响。通过三维有限元数值模拟,研究平缓或缓倾斜煤层、倾斜煤层、急倾斜煤层开采对上覆构筑物基础变形的影响,依据特定构筑物对倾斜变形、水平变形和基础沉降最大值的容许要求,提出安全煤柱（移动角γ、β）的保护范围,为构筑物安全运行和煤矿合理开采提供依据。     

郭二庄9~#煤带压开采底板突水灰色风险评价

针对郭二庄井田下组9#煤带压开采中存在的底板突水风险影响因素的不确定性,采用灰色风险计算模型和方法,结合井田已有突水、出水点水位标高、矿井最大涌水量及单位涌水量等相关信息统计,构建灰色风险计算模型,对井田受采动影响后煤层底板发生突水风险的概率和风险性变异进行评价。计算结果表明郭二庄井田下组9#煤带压开采存在底板突水风险性大,煤层开采前应慎重作出避让和分区隔离开采、探治结合等有效的补救措施,减少突发水害事故的发生。     

郭二庄9#煤带压开采底板突水灰色风险评价

针对郭二庄井田下组9#煤带压开采中存在的底板突水风险影响因素的不确定性,采用灰色风险计算模型和方法,结合井田已有突水、出水点水位标高、矿井最大涌水量及单位涌水量等相关信息统计,构建灰色风险计算模型,对井田受采动影响后煤层底板发生突水风险的概率和风险性变异进行评价。计算结果表明郭二庄井田下组9#煤带压开采存在底板突水风险性大,煤层开采前应慎重作出避让和分区隔离开采、探治结合等有效的补救措施,减少突发水害事故的发生。     

Determining areas in an inclined coal seam floor prone to water-inrush by micro-seismic monitoring

The failure depth of the coal seam floor is one important consideration that must be kept in mind when mining is carried out above a confined aquifer. Determining the floor failure depth is the essential precondition for predicting the water-resisting ability of the floor. We have used a high-precision microseismic monitoring technique to overcome the limited amount of data available from field measurements. The failure depth of a coal seam floor, especially an inclined coal seam floor, may be more accurately estimated by monitoring the continuous, dynamic failure of the floor. The monitoring results indicate the failure depth of the coal seam floor near the workface conveyance roadway (the lower crossheading) is deeper and that the failure range is wider here compared to the coal seam floor near the return airway (the upper crossheading). The results of micro-seismic monitoring show that the dangerous area for water-inrush from the coal seam floor may be identified. This provides an important field measurement that helps ensure safe and highly efficient mining of the inclined coal seam above the confined aquifer at the Taoyuan Coal Mine.     

Roadway failure and support in a coal seam underlying a previously mined coal seam

The influence of an upper, mined coal seam on the stability of rock surrounding a roadway in a lower coal seam is examined. The technical problems of roadway control are discussed based on the geological conditions existing in the Liyazhuang Mine No.2 coal seam. The stress distribution and floor failure in the lower works after mining the upper coal is studied through numerical simulations. The failure mechanism of the roof and walls of a roadway located in the lower coal seam is described. The predicted deformation and failure of the roadway for different distances between the two coal seams are used to design two ways of supporting the lower structure. One is a combined support consisting of anchors with a joist steel tent and a combined anchor truss. A field test of the design was performed to good effect. The results have significance for the design of supports for roadways located in similar conditions.     

Suitable retention and recovery technology of floor coal at ends of fully mechanized face with great mining heights

Gateways at faces of great mining heights are mostly driven along the roof of coal seams. For gateway height restrictions, a 1-3 m floor coal is retained, leaving a triangular floor coal at the face ends, causing a loss of coal. In order to improve coal recovery rates and to ensure efficiency of equipment at coal mining faces, we investigated suitable retention methods and recovery technology of floor coal at face ends. The upper floor coal can directly be recovered by a shearer with floor dinting. The lower floor coal is recovered by shearer with floor dinting after advanced floor dinting and retaining a step for protecting coal sides in a haulage gateway. Field practice shows that this method can improve the coal recovery rates at fully mechanized working faces with great mining heights.     

青东矿10煤层水文地质特征及充水因素分析

为了评价10煤层开采可能产生的水害影响,根据矿井含、隔水层的水文地质特征,指出10煤层受采动破坏,顶底板砂岩裂隙水、太原组和奥陶系岩溶水沿采动裂隙和断层溃入矿井,对矿井开采形成威胁。根据对矿井充水因素的分析,得出矿井的充水强度不大,充水通道主要为隔水层薄弱地段采动裂隙和断层破碎带。     

Simulation of recovery of upper remnant coal pillar while mining the ultra-close lower panel using longwall top coal caving

With the depletion of easily minable coal seams, less favorable reserves under adverse conditions have to be mined out to meet the market demand. Due to some historical reasons, large amount of remnant coal was left unrecovered. One such case history occurred with the remnant rectangular stripe coal pillars using partial extraction method at Guandi Mine, Shanxi Province, China. The challenge that the coal mine was facing was that there is an ultra-close coal seam right under it with an only 0.8–1.5 m sandstone dirt band in between. The simulation study was carried out to investigate the simultaneous recovery of upper remnant coal pillars while mining the ultra-close lower panel using longwall top coal caving(LTCC). The remnant coal pillar was induced to cave in as top coal in LTCC system. Physical modelling shows that the coal pillars are the abutments of the stress arch structure formed within the overburden strata. The stability of overhanging roof strata highly depends on the stability of the remnant coal pillars. And the gob development(roof strata cave-in) is intermittent with the cave-in of these coal pillars and the sandstone dirt band. FLAC3 D numerical modelling shows that the multi-seam interaction has a significant influence on mining-induced stress environment for mining of lower panels. The pattern of the stress evolution on the coal pillars with the advance of the lower working face was found. It is demonstrated that the stress relief of a remnant coal pillar enhances the caveability of the pillars and sandstone dirt band below.     

煤层底板岩体参数概率分布及Bayes优化

正确确定煤系岩体力学参数的概率分布是承压水上采煤底板稳定可靠性分析的关键。以淮北矿区部分煤矿下组煤底板砂岩强度参数为例,以K-S检验法对数据进行概率分布拟合,获取参数分布类型及统计量。以此大样本概型为先验函数,具体工作面底板岩体小样本参数的概型为似然函数,基于Bayes方法对其优化,得到验后分布的概型参数。计算结果表明,下组煤底板砂岩强度参数全部接受正态分布和对数正态分布,优化后的方差有所下降,可以提高底板采动稳定可靠性分析结果,从而达到优化目的。