急倾斜煤层俯伪斜下保护层开采的卸压范围

以某煤矿急倾斜煤层俯伪斜下保护层开采为工程对象,采用有限元数值计算分析方法,从被保护层的应力和变形2个方面分析了保护层开采对被保护层的卸压程度和卸压保护范围;通过现场观测被保护层瓦斯动力参数变化,确定了被保护层实际的有效保护范围.2种方法得到的结果基本一致.结果表明:该矿井保护层开采后被保护层得到充分保护的倾向上部卸压角为90°、下部为82°,走向超前距离大于20 m,其被保护层卸压范围是一个近似椭圆型的卸压圈,卸压圈椭圆的中心区域是卸压效果最充分的区域,从卸压圈椭圆的中心到边界卸压效果逐渐减弱.     

近距离煤层群被保护层开采瓦斯综合治理技术研究

近距离煤层群被保护层回采过程中,由于被保护层与保护层之间距离较小,保护层采空区内积聚的瓦斯通过采动影响所产生的裂隙大量涌入被保护层工作面,容易造成工作面瓦斯超限.本文以新庄孜矿62113被保护层工作面回采为例,通过调节通风负压和抽采系统相结合的瓦斯治理措施,改变工作面及邻近层瓦斯流向,抑制瓦斯涌向回采工作面,从而增加瓦斯抽采量,降低回风瓦斯浓度,有效的保证了工作面的安全回采.     

高瓦斯煤层开采的新思路及待研究的主要问题

提出了解决高瓦斯煤层开采的新思路：在一个密闭的空间中实现瓦斯与煤同采,使采煤工作在一个即能密封又能开放的空间中进行;当采煤机械高速运行、瓦斯涌出量很大量,回采工作面上下巷道密闭,使回采工作空间的瓦斯浓度保持在30％以上,完全处于不能产生爆炸的环境中,使机械设备的效率能够得到充分发挥,实现高产高效安全生产的目标;当工作面出现故障、必须停采处理时,打开工作面上下巷道的风门,恢复通风。煤与瓦斯同采是高瓦斯煤层的一项全新的开采方式,需要对其主要问题进行深入的研究。     

煤层群下保护层开采卸压范围扩界研究

通过开采保护层降低高突出煤层的危险性,作为一种有效的保护措施,在煤矿开采中得到广泛应用。而准确探究近距离煤层下保护层卸压范围,对合理布置保护层,提高卸压效率显得尤为重要。在过去,我们一般认为倾向卸压角度为80°左右,沿走向的保护范围卸压角在56°～60°左右。本文在前人研究的基础上,通过数值模拟及现场考察等方法,获得了近水平上被保护层工作面走向上和倾向上的煤层膨胀变形规律,在下保护层的设计中,为相对原来规定的范围增加扩界区域提供一定的理论支持。走向上通过对其卸压瓦斯的抽采,扩界区域同样可处于有效保护范围内,即走向卸压角可由56°提高至90°左右。倾向上可考虑将卸压角度由80°增大为90°,实现保护层与被保护层的等宽布置。并以淮南朱集矿1111(1)工作面首采保护层的现场监测数据做对照,分析结果与实际值相符。     

突出矿井煤层群开采首采保护层区域消突技术实践

以突出矿井谢桥煤矿为例,介绍了煤层群开采首采保护层卸压瓦斯抽采工程设计和被保护煤层卸压瓦斯抽采效果.实践表明,谢桥矿1242(1)保护层开采实践证明,在11-2煤层有效保护范围内的13-1煤层,可充分消除其突出危险性,并有利于被保护层瓦斯治理;经保护层开采后,不仅能最大程度消除高瓦斯突出危险煤层的瓦斯事故隐患,而且极大地提高了巷道掘进速度,从而缓解了工作面接替的紧张局面,有效提高了生产效率.保护层开采区域消突技术是防治煤与瓦斯突出最经济、有效的技术措施.     

地面钻井抽采远距离保护层卸压瓦斯模拟分析

为研究地面钻井抽采远距离保护层卸压瓦斯效果,以朱仙庄矿Ⅱ1055工作面为例,运用Fluent模拟研究地面钻井抽采下采空区瓦斯分布状况和钻井的抽采效果。结果表明：高浓度卸压瓦斯会堆积在裂隙带和弯曲下沉带内,采空区中部的瓦斯受地面钻井的影响要小于进、回风侧。随着地面钻井距工作面距离的增加,钻井抽采纯量和抽采浓度都会出现先升高后降低的趋势,钻井布置在回风侧且距工作面60～70 m时抽采效果最佳。     

新庄孜矿B8保护层开采对B6煤效果考察实践分析

以突出矿井新庄孜矿为例,介绍了煤层群开采首采保护层卸压瓦斯抽采工程设计及被保护层瓦斯抽采效果。通过在66208工作面回采过程中瓦斯压力测定、瓦斯抽采效果和煤层最大变形量的考察,得出保护层工作面开采后,被保护层B_6煤层透气性系数增大了902倍,B_6煤层残余瓦斯含量为2.43 m~3/t;得出实际走向及倾向方向上的有效保护范围。最大化的回收煤炭资源,取得了较好的效果。     

保护层开采卸压增透效应研究及其定量表征方法探索（研究生论坛稿件）

保护层开采是高突矿井瓦斯治理地主要方式及开采方法,保护层开采的卸压增透效果当前无法量化表征的,缺乏评价体系。以平板流体模型增透率理论为基础,结合平煤十矿地质条件,通过离散单元法建立保护层开采数值模型,获得保护层开采不同距离时采空区下方的增透率图谱及被保护层的应力分布。研究结果表明：保护层开采过程中,采面前方15 m处支撑压力会出现应力峰值,随着采面的推进,增透率与现场瓦斯流量呈现正相关关系;在采空区下方,被保护层卸压以及增透效应明显,且卸压区范围与增透率分布集中区域基本一致,均随着采空区范围的扩大而增大。该研究成果证实了增透率理论可以作为保护层开采卸压增透指标,对现场保护层回采设计、瓦斯抽采设计范围的确定提供了更加科学的依据。     

近距离煤层群首采保护层工作面瓦斯综合治理技术研究

瓦斯治理仍是世界性难题。本文针对赤峪煤矿近距离高瓦斯煤层群首采保护层C0202工作面瓦斯治理问题,提出了沿空留巷Y型通风配合本煤层顺层钻孔、两巷底板穿层钻孔、顶抽巷高位穿层钻孔、采空区埋管的＂五措并举＂治理措施,实现了工作面成功连续留巷200m,瓦斯抽采率高达70%,回风流瓦斯浓度控制在0.4%左右的效果,保证了工作面的安全高效开采。该研究成果可为赋存条件相似的煤层群开采瓦斯治理提供借鉴。     

弱松散含水层下无防砂保护层开采研究

本从理论分析、典型调查、开采试验等三个方面阐述和验证了在弱松散含水层下实现无防砂保护层的煤层开采不仅具有安全性，而且对扩大煤的可采储量、延长矿井服务年限有着重要的意义。     

Effect of protective coal seam mining and gas extraction on gas transport in a coal seam

A gas–solid coupling model involving coal seam deformation,gas diffusion and seepage,gas adsorption and desorption was built to study the gas transport rule under the effect of protective coal seam mining.The research results indicate:(1) The depressurization effect changes the stress state of an overlying coal seam and causes its permeability to increase,thus gas in the protected coal seam will be desorbed and transported under the effect of a gas pressure gradient,which will cause a decrease in gas pressure.(2) Gas pressure can be further decreased by setting out gas extraction boreholes in the overlying coal seam,which can effectively reduce the coal and gas outburst risk.The research is of important engineering significance for studying the gas transport rule in protected coal seam and providing important reference for controlling coal and gas outbursts in deep mining in China.     

Pressure relief, gas drainage and deformation effects on an overlying coal seam induced by drilling an extra-thin protective coal seam

Numerical simulations and field tests were used to investigate the changes in ground stress and deformation of, and gas flow from, a protected coal seam under which an extra-thin coal seam was drilled. The geological conditions were: 0.5 meter min-ing height, 18.5 meter coal seam spacing and a hard limestone/fine sandstone inter-stratum. For these conditions we conclude: 1) the overlying coal-rock mass bends and sinks without the appearance of a caving zone, and 2) the protected coal seam is in the bending zone and undergoes expansion deformation in the stress-relaxed area. The deformation was 12 mm and the relative defor-mation was 0.15%. As mining proceeds, deformation in the protected layer begins as compression, then becomes a rapid expansion and, finally, reaches a stable value. A large number of bed separation crannies are created in the stress-relaxed area and the perme-ability coefficient of the coal seam was increased 403 fold. Grid penetration boreholes were evenly drilled toward the protected coal seam to affect pressure relief and gas drainage. This made the gas pressure decrease from 0.75 to 0.15 Mpa, the gas content de-crease from 13 to 4.66 m3/t and the gas drainage reach 64%.     

高瓦斯矿井一次采全高综采工作面瓦斯治理

介绍了晋城矿区寺河矿高瓦斯矿井一次采全高工作面瓦斯治理方法和瓦斯利用情况,提出了高瓦斯矿井一次采全高工作面瓦斯治理途径和技术,指出高瓦斯矿井高产高效、安全生产的根本出路在于提高瓦斯抽放率,加强瓦斯利用,进而提高矿井的综合效益.     

高瓦斯煤层千米定向钻孔煤与瓦斯共采机理

结合最新引进的德国DDR-1200型千米定向钻机,提出在工作面顶板裂隙带内打千米定向钻孔抽采瓦斯的新方法,构建千米定向钻孔煤与瓦斯共采体系.结果表明,工作面上覆岩层存在大量横向间隙和竖向裂隙,裂隙带高度为34m左右,最大离层裂隙发生在主关键层下方,距离工作面顶板22m左右,最大离层量240mm,形成瓦斯富集区域;工作面倾向方向,回采巷道向采空区方向0～60m范围内裂隙最发育,并能长期稳定存在.据此在14301工作面进行工业性试验,试验结果表明,钻孔布置在14301工作面上方顶板22m左右,倾向方向距运输巷15m处,抽采浓度达70%以上,抽采时间在120d以上,取得最佳瓦斯抽采效果,实现煤与瓦斯共采.     

Mechanical analysis of effective pressure relief protection range of upper protective seam mining

This paper analyzes the control mechanism of coal and gas outbursts and proposes the concept of an effective pressure relief protection range, based on the stress relief of the underlying coal-rock mass and the development of a plastic zone. Also this study developed a stress change and fracture development model of the underlying coal-rock mass. In addition, the stress and depth of fracture of any point in the floor were deduced with the application of Maple Calculation Software. The specific engineering parameters of the Pingdingshan No. 12 colliery were applied to determine the relationship between the depth of fracture in the floor and the mining height. The pressure-relief principle of the underlying coal-rock mass was analyzed while varying the mining height of the upper protective seam. The findings indicate that as the depth of fracture in the floor increases, the underlying coal-rock mass experiences a limited amount of pressure relief, and the pressure relief protection range becomes narrower.Additionally, the stress distribution evolves from a ‘‘U" shape into a ‘‘V" shape. A 2.0 m mining height of protective seam situates the outburst-prone seam, Ji_(15), within the effective pressure relief protection range. The fracture development and stress-relief ratio rises to 88%, ensuring the pressure-relief effect as well as economic benefits. The measurement data show that: after mining the upper protective seam, the gas pressure of Ji_(15) dropped from 1.78 to 0.35 MPa, demonstrating agreement between the engineering application and the theoretical calculation.     

Principle and engineering application of pressure relief gas drainage in low permeability outburst coal seam

With the increase in mining depth, the danger of coal and gas outbursts increases. In order to drain coal gas effectively and to eliminate the risk of coal and gas outbursts, we used a specific number of penetration boreholes for draining of pressure relief gas. Based on the principle of overlying strata movement, deformation and pressure relief, a good effect of gas drainage was obtained. The practice in the Panyi coal mine has shown that, after mining the Cllcoal seam as the protective layer, the relative expansion deformation value of the protected layer C13 reached 2.63%, The permeability coefficient increased 2880 times, the gas drainage rate of the C13 coal seam increased to more than 60%, the amount of gas was reduced from 13.0 to 5.2 m3/t and the gas pressure declined from 4.4 to 0.4 MPa, which caused the danger the outbursts in the coal seams to be eliminated. The result was that we achieved a safe and highly efficient mining operation of the C 13 coal seam.     

“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．     

煤与瓦斯突出矿井煤层群联合开采动态接替研究

针对高瓦斯突出矿井煤层群联合开采的特点,提出了动态编制矿井采掘接替计划的方法.通过对影响矿井采掘工程接替的安全因素和经济因素的分析,建立了影响采掘工程接替的因素指标体系,利用层次分析方法得出了因素的指标权重,采用模糊综合优选法确定备选工作面中的最优接替面,依次类推,直到安排所有的备选工作面.根据采煤工作面生产计划,综合考虑矿井瓦斯治理技术,采用时间反推方法,编制采煤工作面相关的掘进计划.应用研究结果表明,采掘动态接替法可以适时调整采掘接替计划,所得采掘工程接替方案科学合理、切实可行.