Ground pressure and overlying strata structure for a repeated mining face of residual coal after room and pillar mining

To investigate the abnormal ground pressures and roof control problem in fully mechanized repeated mining of residual coal after room and pillar mining, the roof fracture structural model and mechanical model were developed using numerical simulation and theoretical analysis. The roof fracture characteristics of a repeated mining face were revealed and the ground pressure law and roof supporting condi- tions of the repeated mining face were obtained. The results indicate that when the repeated mining face passes the residual pillars, the sudden instability causes fracturing in the main roof above the old goal and forms an extra-large rock block above the mining face. A relatively stable ＂Voussoir beam＂ structure is formed after the advance fracturing of the main roof. When the repeated mining face passes the old goaf, as the large rock block revolves and touches gangue, the rock block will break secondarily under overburden rock loads. An example calculation was performed involving an integrated mine in Shanxi province, results showed that minimum working resistance values of support determined to be reason- able were respectively 11,412 kN and 10,743 kN when repeated mining face passed through residual pillar and goaf. On-site ground pressure monitoring results indicated that the mechanical model and support resistance calculation were reasonable.

Waste-filling in fully-mechanized coal mining and its application

A fully-mechanized coal mining (FMCM) technology capable of filling up the goaf with wastes (including solid wastes) is described. Industrial tests have proved that by using this technology not only can waste be re-used but also coal resources can be exploited with a higher recovery rate without removing buildings located over the working faces. Two special devices, a hydraulic support and a scraper conveyor, run side-by-side on the same working face to simultaneously realize mining and filling. These are described in detail. The tests allow analysis of rock pressure and ground subsidence when backfilling techniques are employed. These values are compared to those from mining without using backfilling techniques, under the same geological conditions. The concept of equivalent mining height is proposed based on theoretical analysis of rock pressure and ground subsidence. The upper limits of the rock pressure and ground subsidence can be estimated in backfilling mining using this concept along with traditional engineering formulae.

Control strategy for multi-pump emulsion power station in coal mine face

Shearer and hydraulic support are matching equipments. To increase the operating speed of the shearer, the following speed of hydraulic support must be increased. This means increasing the volume of flow from emulsion power station. Analyzing the operating characteristics of hydraulic supports, the number of simultaneously operating supports is obtained by means of pressure parameter and time history at a certain time, which is a theory base for development of control system to multi-pump emulsion power station.

New development of sets equipment technologies for coal mine longwall face in China

Background of the development and achievement on sets equipment technologies for coal mine longwall face in China was reviewed initially. On the theoretical side, a coupling model of hydraulic support and surrounding rock, support pa- rameters optimization and threedimensional （3D） dynamic design method were presented. On the practical side, this paper out lined some of practical issues and discussed some relative methods and technologies. In thin seam coal longwall mining, how to lower equipment height is the first problem that should be solved. Roof pressure regularity, control of rooffall and collapse, and hydraulic support stability were investigated preferentially in 5-7 m coal seam longwall mining. The application of equip- ment for longwall mining with 5-7 m cutting height in China was concluded. The characteristics of full-mechanized top coal caving for extra thick seam coal were presented. The automation of top-caving hydraulic support and relevant equipment have achieved important breakthrough. At the end of this paper, further development of China＇s coal industry and longwall mining technologies and equipment were prospected in brief. This paper gives readers a comprehensive understanding of China＇s coal mine longwall face equipment technologies. It will give help to other countries on its coal mining development.

Construction and stability of an extra-large section chamber in solid backfill mining

In solid backfill mining without gangue removal, the gangue is separated directly underground and backfilled into goaf. This necessitates the underground construction of an extra-large section chamber for separation equipments. For the construction of an extra-large section chamber in the Tangshan mine, we proposed an active support through a combination of bolting, anchor cables, lining, and a reinforced chamber floor by inverted arch pouring. ABAQUS software was used to analyze the surrounding rock deformation and the plastic zone development of the chamber under different excavation schemes.The best excavation scheme was determined, and the effectiveness of the combined supports was verified. In practice, the engineering installation showed good overall control of the movement of the surrounding rock, with roof-to-floor and side-to-side convergences of 154.6 and 77.5 mm, respectively,which meets the requirements for underground coal gangue separation.

Primary study on the ＂θ＂ letter type overlying multi-strata spatial structure of mining face surrounded by mined areas

The overlying strata spatial structure academic viewpoint thinks the primary factor which controls the stope presses is the overlying strata spatial structure movement; the spatial structure above the later period coal pillar surrounded by mined areas is the most complex overlying strata spatial structure and study on its evolution law has the important realistic project significance for strata movement control and production safety. The existing research results indicate that the special structure of the first working face of the mine begins to develop lengthways from stratum movement above mined areas and extends level in the exploitation direction. From existing overlying strata spatial structure fundamental research achievement, the spatial structure above the later period coal column surrounded by mined areas have following characteristic： The spatial structure formation is from the top to the lower and from large to small. According to the findings, a formula with the use of rock layer migration angle delta was put forward to estimate isolated island coal column width on which different stratum structure is gonging to form.

基于Simulink的矿用液压支架纯水安全阀性能的研究

根据纯水安全阀的结构组成,对出现的故障问题及使用性能要求进行分析,采用MATLAB/Simulink仿真软件,开展了不同阀芯质量、不同供液流量对安全阀阀口压力的影响情况研究,掌握了安全阀阀口压力在使用过程中的变化规律,提出了采用质量更轻的阀芯材料、确定最佳的供液流量值,以降低安全阀的故障损坏、提高安全阀及液压支架的使用性。

基于差分非平稳Transformer的液压支架立柱压力预测

液压支架立柱压力预测是回采工艺决策的重要依据,也是确保围岩稳定的基础信息之一。然而,液压支架立柱压力虽然具有一定的规律性,却无法用简单的数学模型进行预测;且在回采过程中,支架不接顶、顶板破碎、传感器检测误差等带来大量的随机噪声,使得压力数据劣化为非平稳时间序列,给压力的预测带来的很大的困难。本文在Transformer基础上,提出一种差分非平稳Transformer模型,在Transformer的编码器和解码器中分别引入差分归一化和反归一化操作,以提升序列的平稳性。同时,在Transformer中采用去平稳注意力机制,计算序列元素之间的关联关系,以增强模型的预测能力。在真实的煤矿支架立柱数据集上的对比实验表明,本文提出的差分非平稳Transformer的预测效果达到0.674,表现明显优于LSTM、Transformer和非平稳Transformer模型。

综采工作面分布式蓄能供液系统研究及应用

为解决综采工作面跟机移架速度慢的问题,提出了基于蓄能器的分布式供液系统,并在柠条塔S1204工作面开展了试验应用。根据工作面的采煤工艺和产能要求确定了跟机移架速度,建立了全工作面供液系统仿真模型,对液压支架单架、双架和三架同时移架的动作过程进行模拟并分析影响移架时间的因素,结果表明:为使工作面生产能力提升到1000万t/a,中部液压支架跟机速度要达到12 m/min以上,需采用双架或三架成组移架来满足其移架时间的要求。为解决该工况压力波动大且易产生丢架的现象,提出在液压支架上设置“蓄能器+单向阀”的分布式蓄能稳压方案,以平衡工作面液压系统瞬时大流量供给不足与平均供液能力过剩的矛盾,并给出了基于流量补偿的蓄能器选型方法。仿真分析表明在安装分布式稳压供液系统后,双架和三架成组移架时间分别减少6.2%和11.5%,尤其在受到其他系统用液扰动条件下,双架成组移架时间可缩短15%以上。井下应用结果表明,安装的分布式蓄能供液系统显著降低了成组拉架中的丢架现象,保证了采煤机运行速度达12 m/min以上;对工作面平均日进尺由16.7刀提高到19.8刀起到重要支撑作用,实现了常态化日进尺22刀,达到了年产1000万t的生产能力,研究工作为综采工作面快速成组跟机移架提供了有效解决方案。

基于MATLAB大采高液压支架稳定性仿真研究

针对液压支架存在失稳等重大安全隐患,以某型大采高液压支架为研究对象,对支架前倾、后仰、侧翻、滑移4种失稳进行分析,运用MATLAB仿真的方法对不同采高、底座宽度、极限倾角、煤层倾角、加载载荷下的支架重心高度等进行仿真分析和研究。研究结果表明:随着支架极限倾角的增加,支架重心高度呈现逐渐减小的趋势;随着支架底座宽度增加,支架重心高度呈现逐渐增加的趋势;随着采高高度的增加,最大、最小煤层倾角呈现逐渐减小的趋势;随着支架底座宽度增加,最大、最小煤层倾角呈现逐渐增加的趋势;随着加载载荷增加,煤层倾角呈现逐渐减小的趋势。该研究为液压支架稳定性、安全可靠性提高等方面提供理论基础。

大采高工作面顶板结构模型及液压支架支护阻力计算

针对大采高工作面覆岩垮落范围大,易出现液压支架稳定性差、损坏率高以及支架压死的问题,采用物理模拟、理论分析以及工程实践的方法,对大采高工作面顶板破断结构模型与支架合理支护阻力计算方法进行了研究。结果表明:随着大采高工作面推进,受采空区空间大的影响,顶板将呈现“组合悬梁-非铰接顶板-铰接顶板”结构特征;支架与围岩相互作用体系由支架-组合悬梁结构-非铰接顶板结构-铰接顶板结构组成,揭示了各结构间的相互作用关系并确定了大采高工作面支架工作阻力的计算公式,支架支护阻力应适应覆岩结构失稳运动的变化,承载结构自身重量以及运动产生的附加载荷;结合大同矿区晋华宫煤矿大采高工作面开采条件,计算了工作面支架合理支护阻力并进行了支架选型,矿压监测显示,选择的ZZ13000/28/60型支撑掩护式液压支架能满足顶板控制的要求,保障了大采高工作面的安全回采。

坚硬顶板切顶卸压技术对巷道围岩变形规律影响

针对特厚煤层坚硬顶板、宽煤柱条件下临空巷道面临的高围岩应力、大变形等问题,以老石旦煤矿16403综放工作面为工程研究背景,从宽煤柱顶板侧向破断结构角度对临空巷道大变形的影响因素进行了理论分析,采用数值模拟方法研究了对16402运输巷实施不同切顶卸压方案时,临近采空区的16403回风巷侧向顶板采动应力传递规律,并在现场施工水力压裂钻孔进行切顶卸压,实现临空巷道围岩变形控制。研究结果表明:“低位坚硬岩层悬臂梁+高位坚硬岩层砌体梁”破断结构是特厚煤层宽煤柱临空巷道大变形的主要原因,可采用切顶卸压技术破坏宽煤柱顶板侧向破断结构来控制临空巷道围岩大变形;切顶角变化可使关键块B长度发生改变,切顶角越大,则关键块B长度越小,临空侧顶板载荷向煤柱传递的程度越弱,临空巷道围岩承受的采动应力越小,切顶角为100°时临空巷道围岩垂直应力与变形量最小;在16402运输巷以切顶角100°施工水力压裂钻孔后,16403回风巷顶底板变形量较未实施切顶卸压的16402回风巷减小86.5%,两帮变形量减小87.1%,临空巷道围岩稳定性得到极大提高。

基于三线性应变软化模型的综采工作面煤壁片帮深度解析预测

为预测综采工作面煤壁片帮深度,以煤壁为研究对象,煤壁煤体视作三线性应变软化材料;将直接顶和基本顶视作宏观顶板,建立了宏观顶板与煤层、支架相互作用的承载力学模型,结合边界条件推导了综采工作面煤壁片帮深度解析计算公式,利用该公式研究上湾煤矿12401工作面煤壁片帮情况,分析影响煤壁片帮的因素及影响规律,结果表明:①推导获得的煤壁片帮深度计算公式能够较准确计算综采工作面煤壁片帮深度,能够定量分析顶板特性和支架参数等对煤壁片帮深度的影响。②增加支架初撑力能够降低煤壁片帮深度;增加支架刚度能够降低煤壁片帮深度,但效果较差;增加支架护帮板支护强度,煤壁片帮深度近似线性减小。③顶板厚度和抗拉强度增加,煤壁片帮深度增长,但增长速率随顶板厚度和抗拉强度增加逐渐趋缓。这主要由于顶板厚度和抗拉强度增加,顶板破断步距增大,向采空区内旋转下沉角度增大所致。④综采采高对煤壁片帮深度有很大影响,综采采高增大,煤壁片帮深度近似线性增长。⑤煤体单轴抗压强度增大,煤壁片帮深度减小,顶底板与煤层界面之间的摩擦因数增大,煤壁片帮深度减小。⑥顶板动载系数增大,煤壁片帮深度近似线性增大。

深地煤炭资源安全高效智能化开采关键技术与实践

深地煤炭资源地质赋存复杂,智能化开采是深地资源安全、高效、绿色发展的必由之路。智能化开采成套技术与装备能否适应千米深井复杂地质环境、控制围岩稳定并驱动装备跟随煤层自动推进是影响煤炭安全高效开采、减少作业人员、降低劳动强度的关键。山东能源集团聚焦千米深井智能化开采围岩控制理论,提出了以强度耦合、刚度耦合和稳定性耦合为核心的支架-围岩智能耦合关系,并形成与之相适应的智能耦合控制逻辑;为突破超大采高智能综采开采工艺及超高煤壁围岩控制技术瓶颈,提出了超大采高液压支架工作阻力“双因素控制法”,发明了三滚筒采煤机及其配套开采方法,研制了与超大采高智能综采相匹配的液压支架及配套系统;针对超大采高综放开采智能化放煤理论与围岩控制难题,提出超大采高综放支架-围岩耦合协调采放空间控制方法,创新了超大采高综放“马鞍形”开采工艺,研制了7 m超大采高智能综放开采液压支架及配套系统;研发了无反复支撑、快速循环自移的单元式超前支架,解决了回采巷道超前支护距离长、支护技术与装备适应性差的问题;开发了基于惯导和精准地质模型的智能采煤控制系统,解决了深部矿井工作面设备智能控制及困扰连续生产的难题;搭建了千米深井智能化开采综合管控平台,实现了千米深井重大灾害多源异构数据融合与管控。上述核心技术在山东能源集团赵楼煤矿7302工作面、东滩煤矿3308工作面等多个工作面进行了智能化开采示范建设,取得了良好的应用效果,所获成果整体推动了我国深地煤炭资源安全高效智能化开采水平,可以为类似矿井智能化工作面建设提供理论与技术借鉴。

煤矿智能化液压支架控制系统研究

煤矿智能化开采是煤炭行业未来发展的重要方向。智能化开采的关键技术之一是智能化液压支架控制,其主要作用是实现煤矿井下集控、地面远控,保障煤矿自动化生产。重点分析了智能化液压支架控制系统的配置,主要包括液压支架电液控制系统、工作面视频监控系统、工作面人员定位系统、工作面自动找直系统、工作面智能化集中控制系统等。可以为煤矿智能化提供一定的技术参考。

采煤工作面巷道水力压裂切顶卸压技术研究

某煤矿2304工作面悬顶垮落,造成巷道变形严重。采用水力压裂切顶卸压技术破坏顶板岩层完整性,减小顶板垮落对工作面的破坏。现场工程实践表明,卸压后巷道最大顶底板变形量均在安全范围内,水力压裂切顶卸压取得良好的施工效果。

大采高大中心距液压支架选型设计

根据陕西小保当矿业有限公司一号井132202工作面煤层地质条件,完成了大采高大中心距中部液压支架与过渡液压支架主要技术参数及结构设计,实现了高产高效,为陕西小保当矿业有限公司大采高超长工作面开采技术的发展提供了宝贵经验。

煤矿掘进设备发展及改进研究

掘进设备对煤矿安全生产具有十分重要的意义。随着科技的发展,中国煤矿有必要进一步优化改进掘进设备,使其最大程度地发挥自身优势和作用,为企业带来更好的经济效益。主要分析了煤矿掘进设备的发展现状及设备改进原则,详细阐述了掘进设备的改进方向,并指出了未来掘进设备的发展趋势。

薄煤层工作面“三机”设备选型及布置

为进一步提升煤矿极近距离煤层的开采效率和安全性,降低煤炭开采成本,以某14号煤层为研究对象,结合相关理论计算公式对液压支架、采煤机以及刮板输送机的核心指标进行核算并完成设备的确定;对所选型的综采设备在现场进行布置并对工程实践应用效果进行评估。

煤矿液压支架搬运车液压系统故障诊断方法

煤矿液压支架搬运车液压系统在运行过程中容易出现故障,若处理不及时,会对煤矿开采工程的安全建设造成严重影响。针对这一问题,提出了一种新的液压系统故障诊断方法。根据液压支架搬运车液压系统的工作原理,建立液压系统故障诊断数学模型;提取液压系统故障时域信号特征,获取故障样本均值与方差;分析液压支架搬运车运行状态与运行模式,对液压系统故障进行全方位诊断。通过实验分析,该方法能够在短时间内快速完成故障诊断,且诊断结果的准确率在95.27%以上,可行性较高。