“三软”特厚煤层开采地表沉陷规律研究

洛阳常村煤矿开采煤层为"三软"特厚煤层,井田范围内村庄较多.为了合理回采村庄下煤柱、提高资源采出率,需要掌握该地质条件下的地表移动变形规律及参数.在该矿"三软"特厚煤层工作面建立了地表移动观测站,对地表沉陷进行现场观测,获得了大量的地表沉陷观测资料.通过对实测资料的分析,得出常村煤矿"三软"特厚煤层开采地表沉陷规律及其参数.研究结果表明:与一般地质采矿条件相比,"三软"特厚煤层放顶煤开采具有地表移动角量参数偏小、影响范围大、下沉系数大等特点,地表沉陷呈现塌陷坑及台阶裂缝形态.     

特厚煤层坚硬覆岩柱壳结构特征模型及应用

以大同矿区同忻煤矿石炭系坚硬覆岩特厚煤层开采为工程背景,基于关键层理论分析了同忻矿3-5#煤层特厚煤层综放开采坚硬覆岩的破断特征和采场覆岩结构特征;应用弹性板理论,建立了大空间采场坚硬覆岩柱壳结构力学模型和数学模型.研究表明:坚硬覆岩柱壳结构模型,较好地揭示了同忻矿8105,8106等工作面开采过程中产生大小周期来压、采动影响范围大、易产生冲击载荷等特殊矿压现象的机理.     

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。     

特厚煤层沿空掘巷力源结构特征与围岩协同控制策略

14～20 m特厚煤层小煤柱沿空掘巷围岩控制是当前煤矿巷道支护领域的难题之一.以山煤国际晋北矿区典型的19 m特厚煤层孤岛综放面小煤柱沿空掘巷工程为研究对象,分析了特厚煤层覆岩应力拱、断裂拱大结构特征以及基本顶侧向破断运动规律,建立了特厚煤层沿空掘巷“双力源”结构模型,揭示了“双力源”传递作用机理及其对沿空掘巷围岩稳定性的影响规律,提出了“远场弱化-近场强化”协同控制治理策略,开展了19 m特厚煤层8 m小煤柱沿空掘巷围岩控制现场试验.结果表明：特厚煤层沿空掘巷强矿压显现源于小煤柱侧Ⅰ型力源和实体煤侧Ⅱ型力源叠加作用;采用小煤柱侧(Ⅰ型)和实体煤侧(Ⅱ型)力源结构“水力压裂+深孔爆破”复合弱化后,基本顶周期来压步距降低了约69.6%,有效阻断了采动应力向围岩传递;通过“远场弱化-近场强化”协同控制技术,有效控制了特厚煤层沿空掘巷掘进与回采期间围岩稳定.研究成果为14～20 m特厚煤层小煤柱工作面安全高效开采提供了一定的理论依据与技术支撑.     

急倾斜矿体开采地表沉陷与概化地应力研究

急倾斜矿体开采地表沉陷规律不同于自重应力作用下的煤矿地表移动规律的特点,研究结果表明急倾斜矿体开采地表沉陷的主控因素为：残余构造应力场与成矿应力场、急倾斜矿体的产状、覆岩体结构与节理裂隙的空间展布规律、开采放矿与顶板管理方法。此外,提出了研究急倾斜矿体开采的地表移动规律时必须在煤矿地表移动规律基础上,引入以残余构造应力为主要影响因素,同时包含倾角、岩体结构、放矿规律的4大主控因素;在此基础上,推导了急倾斜崩落法开采矿山地表移动与概化地应力的关系式,并通过实例加以验证,为多主控因素综合机理研究奠定了基础。     

放顶煤开采上覆巨厚砾岩层变形移动规律研究

放顶煤开采时上覆巨厚砾岩层垮落直接影响综放工作面的安全生产,为了研究放顶煤开采上覆巨厚砾岩层变形移动规律,以河南大有能源股份有限公司耿村煤矿综放工作面特厚煤层及其上覆巨厚砾岩层为工程背景,采用相似材料模拟试验,研究了放顶煤开采时上覆巨厚砾岩层变形移动全过程。结果表明:(1)随着煤层开采,依据巨厚砾岩层裂隙场的特征,巨厚砾岩层变形移动和垮落的全过程分为下位和上位垮落过程,其中下位砾岩层初次断裂时垮落体形态为梯形,上位砾岩层断裂控制着地表的变形;(2)当工作面停采后,巨厚砾岩层裂隙演化发展具有较明显的时间效应;(3)下位砾岩层初次垮落步距650. 0 m,周期垮落步距175. 0 m,上位砾岩层初次垮落步距825. 0 m,地表下沉系数0. 267。研究结果可为耿村煤矿巨厚砾岩层下综放开采提供安全技术支撑。     

近直立特厚煤层应力调控防冲方法及机制

近直立特厚煤层的地质与开采条件与一般煤层差异较大,冲击地压防治形势严峻.本文综合采用理论分析、数值模拟、现场监测等方法,研究了近直立特厚煤层动静载力源分布特征,提出了应力调控防冲方法,揭示了其防冲机制,并进行了工程应用.结果表明：近直立特厚煤层主要受水平构造应力作用,水平应力通过工作面两侧的顶底板岩层传递至煤层中,并在巷道上下方形成静载集中区;近直立特厚煤层顶底板岩层难以发生破断,然而顶底板岩层破裂释放能量可形成强动载扰动;动载扰动作用于巷道上下方静载集中区并与集中静载叠加可诱发冲击地压.据此,提出了弱化工作面两侧顶底板岩层和下方煤体的应力调控防冲方法,其防冲机制为：弱化顶底板一方面可弱化岩体传递水平应力的能力进而降低巷道上下方的静载集中,另一方面可降低岩体静载集中进而减弱岩体破裂导致的动载强度;弱化煤体可进一步降低巷道下方静载集中并将静载集中区向深部转移.对近直立特厚煤层现场实施的防冲措施进行了优化设计并确定了关键参数,应用表明,工作面高能级微震事件减少了143～178起、微震事件总能量降幅达90%,未发生冲击显现,工作面冲击危险性显著降低,证实了方法的有效性.研究成果可为近直立特厚...     

厚煤层、特厚煤层综采一次采全高开采法的展望

作者认为在我国厚煤层、特厚煤层开采中,采用综采一次采全高具有广阔的发展前景。文中论述了,在3.5m～4.5m 的厚煤层中,应采用综采一次采全高,在特厚煤层中,特别是厚度在8m 以上时.应采用综采放顶煤开采的基本原因,并构造了供定量研究的经济数学模型。     

煤层开采过程中上覆岩层裂隙演化规律研究

以淮南煤矿典型工作面为例,采用离散元数值软件UDEC(universal distinct element code)对工作面回采过程中上下煤岩体内应力场的变化及直接顶冒落过程进行了模拟,分析了上覆煤岩体裂隙产生、发展的形成过程,得到了上覆煤岩裂隙演化规律。研究结果表明,倾向方向工作面回采后,上覆煤岩体内产生冒落、裂隙带和离层带,在工作面内上角位置产生O型圈裂隙带,裂隙发育最大高度为45m。煤层走向回采方向得到了初期来压步距约50m,周期来压步距约20m,上覆煤岩体裂隙在采空区上方约呈45°角发展,并随工作面的前进由下向上、由后往前依次演变。该结果对于煤与瓦斯共采中瓦斯抽放钻孔方位的布置具有工程指导意义。     

采空区上覆岩体裂隙分形规律的实验研究

以山西省霍州矿务局辛置煤矿2204采掘工作面为原型,利用相似材料模拟实验模拟采空区上覆岩体裂隙的形成过程扣分布状态,运用分形几何理论研究采空区冒落带、裂隙带和弯沉带岩体裂隙的分形规律。实验结果表明：上覆岩体裂隙分形维数随工作面推进经历了由小→大→小并趋于稳定的变化过程,开采结束且岩层基本稳定之后,其分形雏数为采动前分维值的0．5％-5％,且模型采空区边缘地带“三带”的分形维数值较采空区中心的分形维数值大。     

薄煤层开采工作面电磁辐射特征

采用电磁辐射技术及装备对薄煤层开采工作面进行电磁辐射监测,深入分析了薄煤层开采工作面电磁辐射显现特征.研究结果表明:采用沿空留巷巷道布置方式,受上区段采空区影响,工作面上巷电磁辐射强度及波动性都高于下巷;工作面来压前电磁辐射增强,来压后减弱,回采过程中电磁辐射呈现明显周期性;薄煤层冲击地压发生于电磁辐射短时间升高的峰后阶段,区别于厚煤层发生于电磁辐射增大到较高值一段时间,然后下降至低值并持续一段时间后.应用电磁辐射对薄煤层开采工作面进行应力分析及冲击地压预测时应充分考虑其特点,以提高分析预测准确性.     

Control over Surrounding Rocks Deformation of Soft Floor and Whole-Coal Gateways with Trapezoidal Supports

In Gengcun Colliery, Yima Coal Group Co. Ltd.the characteristics of the gateways of thick coal seam and the coal seam is with fully mechanized sublevel caving mining are that the thickness of roof coal seam of gateways is larger, their surrounding rocks are the whole-coal mass and the coal seam is prone to Spontaneous Combustion. With the natural equilibrium arch theory, the reasonable adjacent distance of No. 11 mine-type metal supports was calculated in trapezoidal gateways based on these characteristics. Then, in-situ supporting experiments were carried out. There sults indicate that under the action of virgin rock stress, the width of broken rocks zone of surrounding rocks is 1.7-2.0m in return heading and 1.1-1.3 m in going headway. And their surrounding rocks belong to the Ⅳ-type soften rock and the Ⅲ-type common surrounding rock respectively. Therefore, under the movable abutment pressure, the gateways deformation is serious. It is suggested that the designed gateways have to use pre-broadened cross section to suit their deformation. At the same time, the accumulated water on gateway floor must be drained in time. These measures weretaken in the 1302 and 1304 coal faces in Gengcun Colliery, and the satisfactory results have been obtained.     

Analysis of stability of support and surrounding rock in mining top coal of inclined coal seam

The study analyzes the characteristics of roof movement in mining top coal of inclined coal seam, and establishes the mechanical model of support and surrounding-rock stability in inclined coal seam. Besides, this study carries out the numerical calculation and field observation of roof movement and support stability, and provides the critical control measures. The results show that the fracture firstly appears in middle-upper roof and extends upwards in top coal caving in inclined coal seam; regular and irregular caving zones appear in middle-upper stress concentration region, and the asymmetric caving arch is finally formed. Support load of middle-upper working face is larger than that of the middle-lower face; dynamic load coefficient of upper support is large, and the load on the front of support is larger than that on the rear of it, which leads to poor support stability. Stability of support and surrounding-rock system depends mainly on upper-support stability.     

跨采软岩巷道锚注加固技术的实验研究

针对鲍店煤化北翼采区受放顶煤工作面跨采影响的下部主要岩石集中巷,对巷道采用不同支护形式的支护效果进行了相似模拟试验研究,得到了受跨采影响的软岩巷道在不同支护条件下的变形特征,为同类软岩巷道支护提供了科学的依据。     

Arch structure effect of the coal gangue flow of the fully mechanized caving in special thick coal seam and its impact on the loss of top coal

Based on the characteristics of the top coal thickness of the fully mechanized caving in special thick coal seam,the long distance of coal gangue caving,as well as the different sizes of the coal gangue broken fragment dimension and spatial variation of drop flow,this paper uses laboratory dispersion simulation experiment and theoretical analysis to study the arch structure effect and its influence rule on the top coal loss in the process of coal gangue flow.Research shows that in the process of coal gangue flow,arch structure can be formed in three types:the lower arch structure,middle arch structure,and upper arch structure.Moreover,the arch structure has the characteristics of dynamic random arch,the formation probability of dynamic random arch with different layers is not the same,dynamic random arch caused the reduction of the top coal fluency;analyzing the dynamic random arch formation mechanism,influencing factors,and the conditions of instability;the formation probability of the lower arch structure is the highest,the whole coal arch and the coal gangue arch structure has the greatest impact on top coal loss.Therefore,to prevent or reduce the formation of lower whole coal arch structure,the lower coal gangue arch structure and the middle whole coal arch structure is the key to reduce the top coal loss.The research conclusion provides theoretical basis for the further improvement of the top coal recovery rate of the fully mechanized caving in extra thick coal seam.     

Measurement of overburden failure zones in close-multiple coal seams mining

In the Kaiping Coal field, mining of five coal seams, located within 80 m in the Kailuan Group, #5, #7, #8,#9 and #12 coal seam, is difficult due to small interburden thickness, concentrated stress distributions,high coal seam metamorphism, and complex geological conditions. By using the ZTR12 geological penetration radar(GPR) survey combined with borehole observations, the overburden caving due to mining of the five coals seams was measured. The development characteristics of full-cover rock fractures after mining were obtained from the GPR scan, which provides a measurement basis for the control of rock strata in close multiple coal seam mining. For the first time, it was found that the overburden caving pattern shows a periodic triangular caved characteristic. Furthermore, it is proposed that an upright triangular collapsed pile masonry and an inverted triangular with larger fragments piled up alternately appear in the lower gob. The research results show that the roof structure formed in the gob area can support the key overlying strata, which is beneficial to ensure the integrity and stability of the upper coal seams in multiple-seam mining of close coal seams.     

巨厚煤层冲击地压的防治研究

通过对义煤集团千秋煤矿有冲击倾向巨厚煤层冲击现象现状、特点及影响因素分析,结合该矿的生产实践,提出了适合该条件的冲击危险预测方法及相应解危措施,并进一步提出解危措施效果检验方法以及以上工作失败、冲击地压突发情况下的应急措施;在此基础上建立了适合义煤千秋矿巨厚煤层冲击地压防治的安全开采体系,成功地进行了巨厚煤层的综放开采,从而为有冲击倾向巨厚煤层的安全开采提供了成功范例.     

Simulation Analysis of Coal Mining with Top-Coal Caving Under Hard-and-Thick Strata

1 Introduction A large amount of coal seam with hard coal and hard roof exists in the east mining area of China, such as in the representative mining area of Xuzhou, where the hardness is relatively large (f >2); the roof is hard and the thickness is relatively large (about 20 m). Two key problems must be solved for the suc- cessful application of fully-mechanized coal face with top-coal caving technology: the first is the top-coal falling ability and the second is the control of the hard-and-…     

Huge thick conglomerate movement induced by full thick longwall mining huge thick coal seam

A discrete elemental method was used to study the thickness of conglomerate layer in a full thick seam mining activities under the influence of the law, pointing out the thickness of the conglomerate at different seam mining, and during the destruction and instability of existing state of laws. At 21141 thick seam mining, the face toward the direction of separation between the thick layer of conglomerate rock and the next bit after reaching its maximum capacity due to pull from the bottom of the plastic zone, formed a stratified and hierarchical down collapse. The shape of caving area is a “triangular block”, the length of the plastic zone and face advancement from the linear fit between the height of the plastic zone and the advancing face is a quadratic function of distance, while the top layer of thick gravel layer is the overall bending subsidence trend. Tilting the direction of the face, a thick gob of collapsed conglomerate layer is formed in the coal gob entity on both sides of the thick conglomerate at the top of the overall fracture morphology performance, thus forming a mutual extrusion of articulated block structure. The instability, separation and balance of the thick conglomerate layer in the hinged block stope stress leads to abnormal occurrence of rock burst induced by face as the major factor in the accident. This research reveals the form of stress distribution in the destroyed layer of the thick conglomerate rock, analyzes the stope law of coupling for the pressure burst behavior law for the mining work face, and the choice of preventive measures to provide a theoretical basis and implementation.     

Top coal caving mining technique in thick coal seam beneath the earth dam

It is important to study the mining technology under structures for raising the coal resources recovery ratio. Based on the geological and mining conditions, the top coal caving harmonic mining technique in thick coal seam beneath the earth dam was put forward and studied. The 5 factors such as the panel mining direction, panel size, panel location, panel mining sequence and panel advance velocity were taken into account in this technique. The dam movement and deformation were predicted after the thick coal seam mining and the effects of mining on the dam were studied. By setting up the surveying stations on the dam, the movement and deformation of the dam were observed during mining. By taking some protective measures on the dam, the top coal caving mining technique in thick coal seam beneath the earth dam was carried out successfully. The study demonstrates that harmonic mining in thick coal seam is feasible under the dam. The safety of the earth dam after mining was ensured and the coal resources recovery ratio was improved.