"三软"煤层炮采放顶煤工作面矿压规律研究

通过对红旗井中厚煤层炮采放顶煤工作面矿压观测分析,得出“三软”中厚煤层炮采放顶煤工作面的矿压显现特征,综合评价其支架的适应性与工作状态,为工作面支架选型提供依据,对同类条件下放顶煤工作面开采具有指导意义.     

“三软”煤层炮采放顶煤工作面矿压规律研究

通过对红旗井中厚煤层炮采放顶煤工作面矿压观测分析,得出“三软”中厚煤层炮采放顶煤工作面的矿压显现特征,综合评价其支架的适应性与工作状态,为工作面支架选型提供依据,对同类条件下放顶煤工作面开采具有指导意义.     

综放工作面矿压显现规律研究

通过对平顶山煤业(集团)公司十三矿综放工作面矿山压力及支架的受力特点进行综合分析和研究,探讨了该工作面的矿压显现规律,对于了解综放工作面的矿压规律、合理确定支架的工作阻力和结构型式有一定的借鉴作用,对于加强综放工作面控制、推广应用综放技术有着重要的意义.     

综采液压支架初撑力分析

液压支架初撑力对工作面矿压显现有重要影响,故而研究支架初撑力对围岩、不稳定顶板、支架工作阻力的影响,并确定合理参数,有效改善了顶板矿压显现.     

大倾角变角度综放工作面顶板运移与支架稳定性分析

为解决大倾角煤层变角度综放工作面"支架-围岩"系统稳定性控制的难题,以枣泉煤矿120210工作面综放开采为工程背景,采用平面相似模拟实验、理论分析和现场矿压观测等综合研究方法,重点研究了角度变化过渡区域"支架-围岩"系统稳定性,分析得出了大倾角变角度综放采场围岩变形破坏及支架稳定性的分区域特征.结果表明:在大倾角变角度工作面,上部区域是安全高效生产的主体区域,下部区域是整体稳定性的基础,中部区域是安全高效生产与系统稳定协调转换的关键区域,并提出基于工作面仰伪斜变角度布置、顶煤放出量和支架工作阻力分区域控制的大倾角变角度工作面围岩稳定性控制技术.     

轻型支撑式液压支架在构造复杂矿井综采工作面中的应用

为有效解决传统综采工作面受与工作面煤壁平行或斜交落差大于采高的断层影响,如产生搬家困难、搬家时间长以及整体顶梁组合悬移液压支架支护工作面在炭质泥岩底板遇水膨胀,工作面顶板压力大,悬移支架支柱钻底变成"死柱"难于推进等难题,决定采用轻型支撑式液压支架替换整体顶梁组合悬移液压支架,解决了传统综采工作面受落差影响大于采高导致的搬家时间长,悬移液压支架工作面支柱钻底成"死柱"难于推进等问题,提高了企业的技术经济效益.     

综采支架对采空区流场的影响

综采机械化推进速度快,容易使综采支架顶部、上隅角等处瓦斯超限,综放采空区冒落空间大、遗煤多、漏风量较小,也容易造成采空区遗煤自燃.综采支架的存在,影响工作面向采空区漏风.因此利用Fluent软件,对存在与不存在综采支架两种情况下采空区漏风流场进行了数值模拟.结果表明,没有综采支架和有综采支架情况下采空区的漏风量、漏风风速分布和自燃三带的位置和宽度有很大差别.有综采支架时,工作面向采空区的漏风量较小,致使采空区的风流速度很小,自燃带靠近工作面.为了得到接近实际采空区的风流流动规律,解算采空区流场时需要考虑综采支架的影响.     

金刚煤矿综采支架工作阻力的确定

综采支架工作阻力的大小,直接决定着综采支架的架型和质量,关系到矿井的生产和安全,影响到矿井的经济效益和社会效益。运用国内外对支架阻力的计算方法,借助相似模拟试验,确定了金刚矿3115工作面综采支架工作阻力为2400 kN。现场使用效果表明：使用综合机械化开采经济效益和社会效益明显,不过在确定液压支架工作阻力时,应充分参考同一矿井与拟用综采工作面毗邻区采煤工作面的矿压观测结果,由此获得的工作阻力更加可靠合理,适当降低3115工作面综采支架工作阻力,仍可满足安全生产要求。     

综放工作面矿压显现规律研究

通过对平顶山煤业 (集团 )公司十三矿综放工作面矿山压力及支架的受力特点进行综合分析和研究 ,探讨了该工作面的矿压显现规律 ,对于了解综放工作面的矿压规律、合理确定支架的工作阻力和结构型式有一定的借鉴作用 ,对于加强综放工作面控制、推广应用综放技术有着重要的意义     

高档放顶煤工作面网格支架承载特性研究

通过观测孔庄矿井７１７７工作面ＺＷＭ网格式液压迈步放顶煤支架的阻力,分析了支架承载特性,提出了提高支架工作阻力利用率措施。     

大倾角采煤工作面矿山压力显现规律的研究

通过对峰峰矿区薛村矿 92 71 2工作面矿山压力显现规律的研究 ,探明了大倾角“三软”煤层轻型支架放顶煤回采工艺在开采过程中矿山压力显现规律 ,为矿山支架选型、保证安全生产提供了依据     

Underground pressure characteristics analysis in back-gully mining of shallow coal seam under a bedrock gully slope

We studied underground pressure and its mechanism during back-gully mining in a shallow coal seam under a bedrock gully slope, by means of physical simulation, numerical modeling and field monitoring.The results show that the intensity of underground pressure is related to its relative position at the coalface. The underground pressure is intensive and the support resistance reaches a maximum when the coalface is at the bottom of the gully, whereas the underground pressure is moderate and decreases gradually when the coalface passes the gully. The mechanism of these changes is analyzed when the slope rotated in a reversed direction to the slope dip during back-gully mining and form an unstable, multilateral block hinged structure, due to slipping. The subsidence of multilateral blocks is considerable when the block fragmentation is small, resulting in enormous changes in the underground pressure. With an increase in the mass of the block body, the block displacement will be reduced in conjunction with an increased clamp effect by both the unbroken rocks and broken rocks in the goaf, resulting in a decrease of the underground pressure.     

预掘巷过断层及其矸石井下处理技术

针对采煤工作面过断层速度慢、效率低且影响煤质等缺点，提出工作面快速无矸石过断层清洁开采技术，该项技术的关键有二：一是在断层中预掘巷；二是矸石在井下处理．基于断层中预掘巷的矿压特点，确定出其合理的锚梁网支护方案与支护参数，并采用了掘出的矸石与煤的合理“置换”方式，此项技术在翟镇煤矿得到成功应用。     

单元法测定瓦斯分布及旋转射流驱散积聚瓦斯

详细论述了单元法测定工作面各种瓦斯涌出源的涌出比例以及瓦斯浓度分布的原理和方法,该方法简单易行,便于推广．根据单元法实测知：“U”型通风工作面绝大部分从采空区涌出的瓦斯集聚在上隅角附近,而且上隅角也是整个采空区的漏风汇,因此,上隅角极易形成瓦斯积聚．为了有效地治理工作面上隅角积聚的瓦斯,提出旋转径向射流驱散工作面上隅角积聚瓦斯的新方法,可使上隅角积聚区瓦斯浓度在20min内下降到《煤矿安全规程》规定的1％以下．     

旋转径向射流驱散积聚瓦斯的理论分析

应用混合长度理论，阐述了风流的横向和纵向脉动速度是影响风流横向瓦斯传质速度的主要因素，分析了旋转径向射流可大大地提高了巷道整个断面风流中各处横向和纵向脉动速度，强化风流横向的瓦斯传质，有效驱散局部积聚瓦斯．通过理论分析和实际观测发现，旋转径向射流排放工作面上隅角积聚瓦斯具有3种效应：周期性的不断稀释、驱散并排向巷道主风流、逐转排放工作面上隅角积聚瓦斯的柔性排放效应和瓦斯浓度分布迅速均匀化．试验表明，旋转径向射流可安全、可靠、经济、有效的排放上隅角积聚瓦斯．     

Mode-I-crack compression modeling and numerical simulation for evaluation of in-situ stress around advancing coal workfaces

The relatively high stress probably leads to generation of a fractured or even instable area around a working coalface. Also, the generated weak area often evolves into an easy-infiltrating field of water/gas to greatly increase probability of accident occurrence. To reveal the distribution of high stress around working faces, we put forward the mode-I-crack compression model. In this model, the goaf following a working face is regarded as a mode-I crack in an infinite plate, and the self-gravity of overlaying strata is transformed into an uniform pressure applied normal to the upper edge of the model crack. Solving this problem is based on the Westergaard complex stress function. For comparison, the software RFPA-2D is also employed to simulate the same mining problem, and furthermore extendedly to calculate the stress interference induced by the simultaneous advances of two different working faces. The results show that, the area close to a working face or the goaf tail has the maximum stress, and the stress is distributed directly proportional to the square root of the advance and inversely proportional to the square root of the distance to the working face. The simultaneous advances of two neighboring working faces in different horizontals can lead to extremely high resultant stress in an interference area.     

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-…     

Determining the rational layout parameters of the lateral high drainage roadway serving for two adjacent working faces

To determine the rational layout parameters of the lateral high drainage roadway(LHDR) serving for two adjacent working faces, a mechanical model of the LHDR under mining influence was established, and the overburden fissure, mining-induced stress distribution rules were analyzed. First, the development characteristics of mining-induced overburden fissure and the stress distribution law of the upper section of the working face were analyzed. Second, by analyzing the distribution law of vertical stress at different layers, the lateral distance of the LHDR was determined as 25 m. Third, by analyzing the surrounding rock deformation effect, stress distribution law, and overburden fissure distribution law of the LHDR at the heights of 20, 25, and 30 m away from the roof, the rational horizon of the LHDR was determined to be 25 m. Finally, an example of a LHDR located 25 m above the roof of the No. 2 coal seam and 25 m away from the No. 2-603 working face was presented. Results show that when the No. 2-603 coalface is being mined, the surrounding rocks lag 80 m or even further and the working face tends to be stable. The relative deformations of the roof and floor of the roadway and both of its walls were 583 and 450 mm,respectively. The reduction rate of the roadway section was 21.52%–25.32%. The section of the roadway was sufficient to extract the pressure relief gas in the overburden of the No. 2-605 working face. The average gas concentration and the pure volume at the branch pipeline were 24.8% and 22.3 m~3/min,respectively, showing that the position of high-level boreholes was reasonable.     

综放巷内充填沿空留巷工业试验

针对常村煤矿S2-6综放工作面采用传统技术沿空留巷的难点，进行了巷内充填沿空留巷工业试验．试验分三步进行：第一步，对原巷采用锚梁网索联合支护实施加固，撤掉梯形架棚；第二步，在已加固巷道下一工作面侧煤壁，实施扩帮锚网支护；第三步，在原巷位置实施巷内充填，并加固充填体．结合高水速凝充填材料的性能，通过建立合理的综放沿空留巷的围岩结构力学模型和充填工艺设计，井下工业试验达到了预期效果，留巷断面稳定后超过10m^2．证明了在巷内基本支护为梯形金属支架的巷道中进行综放沿空留巷的可行性，并作了经济效益评价．在此基础上提出了综放巷内充填沿空留巷新技术．     

Side abutment pressure distribution by field measurement

Given the 7123 working face in the Qidong Coal Mine of the Wanbei Mining Group, nine dynamic roof monitors were installed in the crossheading to measure the amount and velocity of roof convergence in different positions and at different times and three steel bored stress sensors were installed in the return airway to measure rock stress at depth. On the basis of this arrangement, the rule of change of the distribution of the side abutment pressure with the advance of the working face and movement of overlying strata was studied. The rule of change and the stability of rock stress at depth were measured. Secondly, the affected area and stability time of the side abutment pressure were also studied. The results show that: 1) During working, the face advanced distance was from 157 m to 99 m, the process was not effected by mining induced pressure. When the distance was 82 m, the position of peak stress was 5 m away from the coal wall. When the distance was 37 m, the position of peak stress away from the coal wall was about 15 m to 20 m and finally reached a steady state; 2) the time and the range of the peak of side rock pressure obtained from stress sensors were consistent with the results from the dynamic roof monitors; 3) the position of the peak pressure was 25 m away from the coal wall.