新集二矿巨厚砂岩顶板覆岩应力位移场数值模拟

采空区覆岩“三带”形成、发展与其应力位移分布密切相关.本文以新集二矿1煤210108工作面采空区巨厚砂岩顶板为研究对象,采用数值模拟方法分析采空区覆岩应力位移场分布,结果可为采空区覆岩破坏及“三带”分布分析提供依据.     

煤矿开采复合顶板结构面应力分布特点分析

采用ANSYS程序数值模拟了煤矿开采复合顶板结构面剪应力和法向应力并分析了其分布特点,结果表明:不同原岩应力结构面剪应力分布规律基本相同;结构面法向应力分布和原岩应力及复合顶板岩性有关,深部开采软弱岩性复合顶板结构面法向应力主要呈现拉应力。     

近距离煤层开采侧向支承压力分布的相似模拟试验研究

采用相似模拟的方法,以平顶山八矿己二采区己15和己16-17煤层实际地质资料为基础,分析了近距离煤层上煤层开采时,在上煤层采场两侧向的支承压力分布及集中程度、峰值距煤壁的距离、支承压力的影响范围;一定范围内底板中集中应力的传递及渐衰减特征.研究了上煤层开采后下煤层开采过程中,采煤工作面两侧应力降低区范围、峰值应力的位置、应力集中的程度以及与上煤层开采时的对比关系.作者认为,下煤层开采后上覆顶板岩层受到二次扰动,其破坏移动主要是沿原有破裂面滑移,由于剪胀的作用,上覆岩层能够形成面接触的覆岩基本结构特征.根据模拟结果得出:特定开采条件下,上部或下部不同煤层采煤工作面侧向卸压区范围.该结果对区段巷道布置有一定的参考价值.     

近距离煤层开采侧向支承压力分布的相似模拟试验研究

采用相似模拟的方法，以平项山八矿己二采区己15和己16-17煤层实际地质资料为基础，分析了近距离煤层上煤层开采时，在上煤层采场两侧向的支承压力分布及集中程度、峰值距煤壁的距离、支承压力的影响范围；一定范围内底板中集中应力的传递及渐衰减特征．研究了上煤层开采后下煤层开采过程中，采煤工作面两侧应力降低区范围、峰值应力的位置、应力集中的程度以及与上煤层开采时的对比关系．作者认为，下煤层开采后上覆顶板岩层受到二次扰动，其破坏移动主要是沿原有破裂面滑移，由于剪胀的作用，上覆岩层能够形成面接触的覆岩基本结构特征．根据模拟结果得出：特定开采条件下，上部或下部不同煤层采煤工作面侧向卸压区范围．该结果对区段巷道布置有一定的参考价值．     

基于煤体强度软化特性的综放沿空掘巷巷帮受力变形分析

基于深井综放沿空掘巷巷帮围岩受力特征,考虑巷帮与顶底板界面煤岩体强度软化特性,建立了实体煤帮和煤柱帮力学分析模型,推导出两帮极限平衡区宽度和煤体应力位移理论计算,明确了煤层埋深、巷道高度、煤层顶底板界面软化系数和界面强度参数等因素对煤体极限平衡区宽度、围岩应力和位移分布的影响规律,给出了工程建议措施,并通过现场工程实例对理论分析成果进行了初步应用.研究表明:极限平衡区宽度随煤层埋深、巷道高度及顶底板界面软化系数的增加而增大,随界面强度参数的增加而降低;煤体围岩应力和位移分布沿应力极限平衡区宽度呈双曲函数分布,极限平衡区内围岩竖向应力和水平应力随煤层埋深及界面强度参数的增加而增大,随巷道高度及界面软化系数的增加而降低;极限平衡区内煤体水平位移随煤层埋深、巷道高度、界面软化系数的增加而增大,随界面强度参数的增加而降低.     

内错式下分层回采巷道围岩变形破坏机理研究

利用非线性有限元数值计算方法,模拟了上分层回采巷道开挖、上分层回采及下分层回采巷道开挖三个过程,经过分析得出了下分层煤体内应力分布曲线、内错式下分层回采巷道两帮煤体破坏过程及两帮位移分布特征;室内相似材料模拟试验结果显示了底板岩层竖直应力分布规律及采空区上覆岩层破坏形式。     

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.     

松软煤体中锚杆支护锚固体形成机理分析

通过对松软煤体锚杆支护稳定性影响因素分析,利用数值模拟方法研究了松软煤体中锚杆作用机理,进而分析了松软煤体中锚固体形成条件.结果表明,高预紧力锚杆支护作用下,树脂端锚体与松软煤体间的错动、滑移及在应力重新分布过程的锚杆滑脱与护表构件失效是松软煤体中锚杆支护失效的主要原因;松软煤体进行单根预紧力锚杆锚固后,锚杆轴向应力、附加应力场及位移场随预紧力提高而增大,但附加应力场(锚固体)成型范围受预紧力限制,即随着预紧力(40 kN→60 kN→80 kN)增加,自由段两端附加应力场(锚固体)会出现"一定程度叠加→较大叠加范围→不能相互叠加"的过程,整体锚杆自由段轴向应力分布均匀;多根预紧力锚杆支护产生的附加应力场相互叠加形成锚固体,松软煤体强度特征是形成锚固体的首要条件,可控条件为松软煤体强度与锚杆(较小)预紧力的匹配、增加锚杆长度与支护密度.     

荷载横向变位下箱梁剪滞效应分析

为了研究荷载横向变位下对箱梁剪滞效应的影响,对箱梁底板、顶板及悬臂板分设不同的纵向位移差函数,采用二次抛物线作为箱梁翼缘板的纵向位移沿梁宽分布函数,基于能量变分原理,建立了考虑剪滞效应的箱型梁控制微分方程;分析了荷载在箱梁顶板横向变位下底板、顶板及悬臂板应力的变化规律,根据对简支箱梁在均布荷载作用下跨中剪力滞系数的计算...     

基于微震裂缝参数反演的深部矿井"两带"结构规律

微地震监测可以有效监测煤矿在采煤作业中裂缝事件的发育过程,探讨深部矿井采煤作业进程的微地震地质参数,能够有效确定煤矿放顶煤作业中断裂带与垮落带("两带")的发育高度.采用矩张量反演计算推导深部矿井在采煤作业中引起微地震事件的震源机制,在此基础上求解推导放顶煤采煤法诱发的"两带"裂缝事件点的地质特征参数.通过计算得到剪切型裂缝的方位角分布规律和深部矿井采煤工作面实测的应力分布,构建放顶煤采煤法下采煤工作面顶板的剪切型应力裂缝模型,分析微地震发展演化与"两带"活动规律,对解释采煤工作面的周期来压、"两带"边坡角、采煤工作面应力场的特征分布等重要理论问题和保证矿山安全生产具有重要意义.     

Overburden fracture evolution laws and water-controlling technologies in mining very thick coal seam under water-rich roof

Considering the danger of water inrush in mining very thick coal seam under water-rich roof in Majialiang Coal Mine, the universal discrete element (UDEC) software was used to simulate the overburden fracture evolution laws when mining 4# coal seam. Besides, this study researched on the influence of face advancing length, speed and mining height on the height of the water flowing fractured zones (HWFFZ), and analyzed the correlation of face advancing length and change rules of aquifer water levels and goaf water inflow. Based on those mentioned above, this research proposed the following water-controlling technologies: draining the roof water before mining, draining goaf water, reasonable advancing speed and mining thickness. These water-controlling technologies were successfully used in the field, thus ensured safely mining the very thick coal seam under water-rich roof.     

Systematic principles of surrounding rock control in longwall mining within thick coal seams

Effective surrounding rock control is a prerequisite for realizing safe mining in underground coal mines.In the past three decades, longwall top-coal caving mining(LTCC) and single pass large height longwall mining(SPLL) found expanded usage in extracting thick coal seams in China. The two mining methods lead to large void space left behind the working face, which increases the difficulty in ground control.Longwall face failure is a common problem in both LTCC and SPLL mining. Such failure is conventionally attributed to low strength and high fracture intensity of the coal seam. However, the stiffness of main components included in the surrounding rock system also greatly influences longwall face stability.Correspondingly, surrounding rock system is developed for LTCC and SPLL faces in this paper. The conditions for simultaneous balance of roof structure and longwall face are put forward by taking the stiffness of coal seam, roof strata and hydraulic support into account. The safety factor of the longwall face is defined as the ratio between the ultimate bearing capacity and actual load imposed on the coal wall.The influences provided by coal strength, coal stiffness, roof stiffness, and hydraulic support stiffness,as well as the movement of roof structure are analyzed. Finally, the key elements dominating longwall face stability are identified for improving surrounding rock control effectiveness in LTCC and SPLL faces.     

Coupling effects of coal pillars of thick coal seams in large-space stopes and hard stratum on mine pressure

Concerning the issue of mine pressure behaviors occurred in fully mechanized caving mining of thick coal seams beneath hard stratum in Datong Mining Area, combined with thin and thick plate theory, the paper utilizes theoretical analysis, similar experiments, numerical simulations and field tests to study the influence of remaining coal pillars in Jurassic system goaf on hard stratum fractures, as well as mine pressure behaviors under their coupling effects. The paper concludes the solution formula of initial fault displacement in hard stratum caused by remaining coal pillars. Experiments prove that coupling effects can enhance mine pressure behaviors on working faces. When inter-layer inferior key strata fractures, mine pressure phenomenon such as significant roof weighting steps and increasing resistance in support.When inter-layer superior key strata fractures, the scope of overlying strata extends to Jurassic system goaf, dual-system stopes cut through, and remaining coal pillars lose stability. As a result, the bottom inferior key strata also lose stability. It causes huge impacts on working face, and the second mine pressure behaviors. These phenomena provide evidence for research on other similar mine strata pressure behaviors occurred in dual-system mines with remaining coal pillars.     

提高炮采工作面块碳率的爆破技术研究

针对永城煤电集团公司陈四楼煤矿三个炮采工作面的具体情况 ,对炮采工作面提高块碳率的微差爆破技术参数进行了理论分析和现场试验 ,确定了软煤体、片帮和破碎顶板条件下合理的爆破参数 .在安全、高效的前提下 ,块碳率提高了 6%～ 1 0 % ,取得了良好的经济效益     

对厚煤层综采面煤壁片帮冒顶严重的原因分析

通过对综采面围岩结构的分析 ,论述厚煤层工作面煤壁产生片帮冒顶的机理 ,进而分析了易片冒区 (ABC)的面积、变形量与煤层厚度的关系 ,从而说明了厚煤层综采放面煤壁片帮冒顶严重的原因     

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.     

厚煤层分层开采再生顶板和设备配套问题研究

研究了分层综采采空区注浆工艺和下分层开采再生顶板岩层结构,据分层综采工作面设备配套特征,提出了工作面液压支架设备选型的要求,进而对我国高产高效矿井建设模式进行分类,总结了分层综采工作面设备配套方案.     

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.     

FLAC3D在张集煤矿开采沉陷预测中的应用分析

利用FLAC~(3D)数值分析软件,分析了高潜水的张集煤矿巨厚松散层下12171工作面重复开采对上部17278工作面移动变形区的走向位移、垂直应力分布和塑性破坏区的影响。分析结果表明:数值模拟结果与实测数据基本相符;多煤层重复采动地表下沉具有特殊性,下沉量相比于初次采动是逐渐增大的,随着重复采动次数的增加,下沉量逐渐趋于稳定;同时随着工作面累计推进距离的增加,地面沉陷范围逐渐增加,并形成塌陷盆地;两工作面顶板围岩以剪切破坏为主,局部发生拉伸破坏。     

华丰井田4煤层顶板砾岩水突出影响因素分析

在分析砾岩分布特征及其水文地质特征的基础上,以矿山压力控制理论为指导,运用岩层沉降理论推断了华丰矿1409工作面在采厚为6.5m的情况下,导水裂隙带发育高度为96.2m,揭示了导水裂隙能够导致顶板砾岩水突出.结合矿山压力观测资料和顶板突水量资料,阐述了矿山压力和顶板砾岩突水突出之间的因果影响关系.根据2407工作面冲击地压监测资料,阐明冲击地压对顶板突水的促进作用.建立了顶板水沿工作面下平巷突出运移的模型,阐明了斑裂线是导致砾岩水大量突出的主要导水通道.