近距离房采煤柱下回采巷道失稳机理数值模拟研究

近距离房采煤柱下长壁开采将受到工作面顶板动压和上覆煤柱集中应力的共同影响,导致工作面剧烈来压从而引发回采巷道失稳事故。针对神东矿区大柳塔矿22202工作面潜在的巷道失稳事故问题,采用数值模拟研究了房采煤柱下长壁开采顶板的应力演化及运动规律,分析了回采巷道围岩的应力和变形特征。研究结果表明,工作面进入房采煤柱下方后,支承应力峰值点超前工作面距离会显著减小,造成超前支承峰值和工作面的顶板力叠加,在顶板来压和叠加应力共同作用下将引发巷道失稳事故;在房采煤柱采空区边缘前后20m范围内顶板运动和应力分布不稳定,巷道失稳事故发生的规律性差;远离采空区边缘60m后,顶板来压周期性明显,巷道失稳事故会周期性地发生。

近距离房采煤柱下长壁工作面压架机理

针对神东矿区大柳塔矿22202工作面可能存在顶板剧烈来压和压架事故等问题,采用理论分析和数值模拟方法研究长壁开采应力演化规律及压架机理。结果表明,工作面进入房采煤柱下方后,支承应力峰值点超前工作面距离会显著减小,造成顶板应力和超前支承峰值应力叠加,使应力集中更加明显。当工作面处于煤柱正下方时,如果顶板来压,在集中应力共同作用下将引发压架事故;在房采煤柱采空区边缘顶板运动不稳定,压架发生的规律性差;远离采空区边缘后,顶板来压的周期性明显,压架事故将会周期性地发生。

黄陵一号井连续采煤机房柱式采煤法应用分析

对黄陵一号煤矿采用的连续采煤机房柱式采煤系统进行分析探讨,并提出了克服冒顶现象的一些技术措施。

房采区下覆综采工作面矿压规律实测分析

为了分析房采区下覆工作面顶板压力影响,以大柳塔煤矿22202综采面为研究对象,对上覆房采区不同支护煤柱对工作面顶板压力的影响进行了分析。结果表明:房采采空区下顶板周期来压步距与实体煤下无明显差别;支架循环末阻力房采采空区下比实体煤下大10. 8%,来压时支架循环末阻力房采采空区下比实体煤下大9. 6%;大小两种煤柱尺寸段下工作面周期来压步距、显著运动步距、支架工作阻力和动载系数均无明显差异,但大煤柱段顶板下沉量为小煤柱段的3. 47倍,达到相同顶板控顶效果(顶板下沉量)时,大煤柱下工作面矿压显现(支架工作阻力)会更强烈。

浅埋房采区下近距离煤层开采动载矿压机理

浅埋煤层工作面房采区下开采易发动载矿压甚至压架等灾害事故。以石圪台矿31201综采工作面典型房采煤柱下动载矿压的案例为基础,采用现场实测、理论分析、数值模拟和物理模拟手段对此类动载矿压发生的机理进行深入研究。研究结果表明:房采煤柱较集中煤柱更易失稳破坏;在下煤层采动和超前支承压力的影响下,房采煤柱突然大范围的失稳破坏会导致其上方关键层发生超前断裂,关键块体的逆向回转将过大的覆岩载荷传递至下方岩层结构,最终导致下位关键块体发生滑落失稳,这是造成工作面发生强烈动载矿压的根本原因。针对易发此类动载矿压的条件,从阻止或转移上覆岩层载荷的角度提出几点针对性的防治措施,其有效性和实用性得到了31201工作面后续安全开采的证实。

Roadway layout for recycling residual coal pillar in room-and-pillar mining of thick coal seam

In the context of a room-and-pillar mining gob in Shanxi province in China,this paper numerically investigates the stress distribution and deformation rules of roadway surrounding rocks at various locations of residual coal pillars in room-and-pillar mining gobs using software FLAC3 D.It is found that the concentrated stress beneath coal pillars distributes in a shape of ellipse.A reasonable roadway layout is then proposed.In this design,it is indicated that roadways should be designed to avoid the supporting zones of pillars with increasing compression and take into account the roof falling and crushing in the upper gob.According to the surrounding rock deformation characteristics and mining roadway locations as well as the supporting principles of timely support,rock reinforcing,piecewise management and suiting local conditions,a new asymmetric shield supporting plan is proposed.The field surveying results show that this supporting plan can effectively control the roadway rock deformation,thus guarantee the safe and smooth construction of roadways.

Surveying on two-zone height of sublevel strip mining

The site drilling packer permeability test and TEM to the 2100 workface in Gucheng coalmine determined the two-zone height under sublevel strip mining.The conclusion considers that the lying strata deterioration law of the strip mining is similar to that of the sublevel mining.Thus, against that the actually measured data lacked, it is feasible to refer to the reservation of the waterproof coal pillar in the neighbor coalmine under sublevel situation.However, it is necessary to further launch the research on lying strata deterioration law under sublevel striping mining for the purpose of providing the right foundation for the layout of the workface not mined so far and the reservation of the waterproof coal pillar in the mining area.

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.

MODELING OF OVERBURDEN FAILURE UNDER THE CONDITION OF MINING TWO CLOSE-RANGE SEAMS USING ROOM-AND-PILLAR ANDLONGWALL MINING

In this paper, the effect of the remaining coal pillars in a room and pillar section on the long wall face in the lower coal bed are tested by using equivalent material models. The failure laws of the overburden under coal pillars are discussed. A phenomenon of sub weighting has been observed when long wall face is in process under the remaining pillars in room and pillar mining section. It is concluded that, because coal pillars underwent a course of the stress increasing before they were fully destroyed, the existence of the coal pillars would shorten the distance of periodical weighting of the main roof in the long wall face. Based on this, the characteristic equations of the overburden movement under coal pillars are presented.

浅谈薄煤层工作面开采技术

世界上薄煤层有着丰富的储蓄量,而对它们的开采工作则进展较少。由于资源供应的日益紧张,人们渐渐将目光集中向薄煤层的开采工作,这成为将来煤炭资源开采的一个发展趋势。文章首先阐述了现阶段薄煤层的开采状况,再重点对薄煤层开采技术进行了叙述,最后对薄煤层开采未来的发展方向进行了讨论。