设置顶板道解决综放工作面瓦斯超限问题的局限性

针对通过设置顶板道来解决综放工作面瓦斯超限技术的广泛应用问题 ,分别较深入地探讨了顶板道和回风巷风量变化与其排放瓦斯量之间的关系。研究表明 ,一般情况下设置顶板道可以较好地解决综放工作面的瓦斯超限问题 ,但瓦斯严重超限时 ,顶板道的排放瓦斯能力难以满足需要 ,在满足回风巷风速及瓦斯浓度均不超限的条件下 ,可通过增大其风量来提高综放工作面总的排放瓦斯能力 .

放顶煤开采顶板道位置合理确定

本文采用数值分析的方法，研究了巷道距采空区距离和采空区压实状况对围岩应力和变形的影响，确定了顶板道合理位置。

煤矿顶板淋水巷道的围岩控制技术研究

煤矿井下开采工作的不断推进,会受到井下恶劣环境、开采扰动和地质特点等方面影响,围岩控制工作存在较多挑战,以顶板淋水巷道的掘进为例,需要针对淋水影响,强化支护工作。为此,基于对案例煤矿基本概述及顺槽掘进问题的了解,首先提出了巷道围岩控制的理论策略,然后结合实际掘进情况,从多方面着手制定了临时支护、永久支护、疏排水、施工管理等围岩控制方案。在实际应用围岩控制方案后,支护效果整体良好,可以降低巷道淋水的影响,提高煤矿井下开采作业的安全性。

高档工作面机道上方顶板的管理

从采煤机机身宽度、截深、进刀方式及顶梁布置方面,介绍了高档普采工作面机道上方顶板的管理方法。

临渊环境的廊道顶板施工中可移动整体支架模板的开发与应用

本工程在廊道悬挑顶板的施工中成功运用了可移动整体支架模板,取代了传统的满堂架子管支撑工艺。不但大大提高了安全性,而且具有支拆效率高、便移动、易周转等优点。摆脱了对机械的依赖,完全依靠人工即可轻松实现,进而降低了工程成本,其设计理念和使用方法值得在类似的工程中推广。此外,本工艺在保证混凝土表面平整度、前沿顺直度等方面也发挥了巨大作用。

贮煤场暗道设计问题探析

通过对贮煤场地下暗道顶板压力在不同情况的分析,及用ANSYS软件对暗道形状的模拟分析,得出了暗道顶板设计时计算竖向压力应考虑的因素及暗道形状的优劣比较.

Deformation mechanism and roof pre-splitting control technology of gob-side entry in thick hard main roof full-mechanized longwall caving panel

This paper explores the deformation mechanism and control technology of roof pre-splitting for gob-side entries in hard roof full-mechanized longwall caving panel(LTCC).The investigation utilizes a comprehensive approach that integrates field monitoring,theoretical analysis,and numerical simulation.Theoretical analysis has illuminated the influence of the length of the lateral cantilever beam of the main roof(LCBM)above the roadway on the stability of the gob-side entry behind the panel.Numerical simulations have further revealed that the longer LCBM results in heightened vertical stress within the coal pillar,developed cracks around the roadway,and more pronounced damage to the roadway.Moreover,numerical simulations also demonstrate the potential of roof pre-splitting technology in optimizing the fracture position of the hard roof.This technology significantly reduces the length of the LCBM,thereby alleviating stress concentration in the coal pillars and integrated coal rib while minimizing the destruction of the gob-side entry.Therefore,this manuscript first proposes the use of roof pre-splitting technology to control roadway deformation,and automatically retain the entry within a hard roof LTCC panel.Field implementation has demonstrated that the proposed automatically retained entry by roof pre-splitting technology effectively reduces gob-side entry deformation and achieves automatically retained entry.

刘老涧三线船闸上闸首裂缝研究

船闸闸首的裂缝问题是船闸施工过程中的一个普遍问题,江苏宿迁市境内于2005年同年开工的皂河船闸、泗阳船闸、刘老涧三线船闸以及2005年已竣工的宿迁船闸,尽管施工中采取了一系列的防裂措施,但船闸闸首在混凝土浇筑拆除模板后,均陆续出现不同程度的裂缝。通过对刘老涧三线船闸集中式输水船闸闸首在施工过程中产生的裂缝情况分析和研究,找出裂缝产生的主要原因,并阐述了相应的预防措施,为今后船闸在设计和施工中避免裂缝产生所要采取的预防措施提供借鉴。

Stability analysis for main roof of roadway driving along next goaf

Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and the sliding stability coefficient K 1 and the rotation stability coefficient K 2 are proposed to describe the stability of the triangle block structure quantitatively. The structure can keep a self stability before and after the roadway excavation, at the stage of mining induced effect, the stability of the structure is lowered, and the structure may become instability with decreasing the coal strength, increasing the mining height of working face and the mining depth.

Mechanism and technology study of collaborative support with long and short bolts in large-deformation roadways

Common short bolts of equal length are widely used to support the roofs of roadways in coal mines.However, they are insufficient to keep the roof stable against large deformations, so docking long bolts with high levels of elongation that can adapt to large deformations of the surrounding rock have been adopted. This paper proposes a collaborative support method that uses long and short bolts. In this study,the mechanism of docking long bolts and collaborative support was studied. Numerical simulation, similarity simulation, and field testing were used to analyze the distribution law of the displacement, stress,and plastic failure in the surrounding rock under different support schemes. Compared with the equal-length short bolt support, the collaborative support changed the maximum principal stress of the shallow roof from tensile stress to compressive stress, and the minimum principal stress of the roof significantly increased. The stress concentration degree of the anchorage zone clearly increased. The deformation of the roof and the two sides was greatly reduced, and the subsidence shape of the shallow roof changed from serrated to a smooth curve. The roof integrity was enhanced, and the roof moved down as a whole. Plastic failure significantly decreased, and the plastic zone of the roof was within the anchorage range. The similarity simulation results showed that, under the maximum mining stress,the roof collapsed with the equal-length short bolt support but remained stable with the collaborative support. The collaborative support method was successfully applied in the field and clearly improved the stability of the surrounding rock for a large deformation roadway.

Test and application of hydraulic expansion bolts in a roadway under goaf with ultra-close separation

The roof of a roadway under goal with ultra-close separation consists of thin rock strata and rocks caving in upper goal. Influenced by the mining of the upper coal seam, the roof is loose and broken, and its integ- rity is poor. Resin anchored bolts cannot provide an effective anchoring force in such roof conditions. By conducting free expansion tests and field pull-out tests on a hydraulic expansion bolt, this study has ana- lyzed the influencing factors and laws of radial expansion and anchoring force changes in the rod body. This has revealed the anchoring mechanism of such bolts, and has obtained reasonable water injection pressures and suitable drilling diameters （which are 20-25 MPa and 32-35 mm respectively） for the hydraulic expansion bolt （cR28 mm） used in these tests. Based on pull-out tests at different interlayer spacing, the applicability of hydraulic expansion bolts had been verified for controlling the roof of road- ways under goal with ultra-close distance. Combined with the deformation and failure characteristics of the test roadway roof, this paper proposes a united roof-control technology based on the use of hydraulic expansion bolts and advancing intubation for the roof. Engineering practice indicated that the roof of the test roadway did not generate leaking and caving phenomenon, and the amount of roof deformation was controlled to within 150 mm. Maintenance of the roadway roof has been improved significantly, which ensures safe mining in coal seams with ultra-close separation.

Mechanism and practice of rock control in deep large span cut holes

Deep large span cut holes are difficult to stabilize. The 7801 cut hole in the Lu'an Wuyang Mine was used as this project's background. The main factors affecting large span cut hole stability are analyzed. Pre- stressed bolting theory was used to design a roof control method for a large span roadway. By reducing the span and applying equal strength coordinated supports the rock could be stabilized. The control prin- ciples and methods are given herein along with the analysis. A double micro arch cross section roadway is defined and its use in solving the current problem is described. Beam arch theory was used to build a model of the double micro arch cross section roadway. A support reverse force model for the arch foot intersection was also derived. A support method based upon reducing the width of the large span in the cut hole is presented. These results show that the reduced span of the roadway roof plus the use of cable anchors and single supports gives an effective way to control the large span cut hole. On site monitoring showed that the reduced span support from the double micro arch cross section roadway design had a significant effect. The roadway surface displacement was small and harmful deformation of the cut hole was effectively controlled. This will ensure its long term stability.

Characteristics of in situ stress field at Qingshui coal mine

In this study, the characteristics of geological structure at Qingshui coal mine were analyzed. And the hollow inclusion strain cell overcoring method was used to obtain the in situ stress. The effect of in situ stress on the stability of soft rock roadway was analyzed. The results show that the maximum principal stress is in the horizontal direction with a northeast orientation and has a value of about 1.2–1.9 times larger than gravity; the right side of roadway roof and floor is easily subject to serious deformation and failure, and the in situ stress is found to be a major factor. This paper presents important information for developing countermeasures against the large deformation of the soft rock roadway at Qingshui coal mine.

刨煤机在大倾角厚煤层倾斜分层开采工作面中的应用

介绍了刨煤机在大倾角厚煤层倾斜分层工作面开采中的工艺过程和刨煤机机组防滑、采高控制与机道顶板管理等关键技术措施。

鲁班山北矿顶、底板拦截抽放在煤层瓦斯治灾中的应用

鲁班山北矿为高瓦斯矿井,如何实现矿井安全生产,杜绝瓦斯事故,瓦斯抽放是最有效的治理措施之一,但常用的瓦斯抽放方法已很难解决特殊条件下的瓦斯涌出。基于此,文章主要介绍了在鲁班山北矿实验成功的工作面顶、底板瓦斯抽采道中的拦截抽放。

Study of dynamic pressure roadway supporting scheme under condi- tion of thick composite roof

This paper analyzed the strata behaviors of solid-coal roadway, gob-side entry driving and deformation law of surrounding rock in depth under high stress and thick composite roof based on the dynamic pressure roadway as engineering background in Fengcheng mining area, Jiangxi province. The results, both field measurement and numerical simulation show that gob-side entry driving results the deformation of coal roadway main wall, however, entity-coal roadway driving results deformation of main roof and floor. The maintenance state of gob-side entry driving is better than entity-coal roadway, this situation is relevant to thick composite roof layered and easy collapse characteristics. At the same time, this paper put fox＇ward and proved proper dynamic pressure roadway supporting scheme under the surrounding rock condition and stress environment.

Underground pressure appearance laws analysis for fully mechanized top coal slice caving on high-dipping thick coal seams

Taking Adaohai Coal Mine as the example, underground pressure appearance laws of fully mechanized top coal slice caving on high-dipping and thick coal seams. Through site visit, theoretical analysis and discrete element calculation, the research shows that, as the mining deepens, underground stress of lower sublevels is more obvious and higher than that of upper sublevels and is higher in the air return roadway than that in the air intake roadway in the area that is near to the top coal. Because the top coal is thick and gangue is caved above the support, underground pressure to the working face is relatively gentle. Immediate roof will mainly fall down along the floor. Main roof and the rock bed above the main roof will move to the mined out area along the fault in the early stage and then fall down with the mined out area later. In addition, roof pressure mainly periodically appears in two directions along the trend and the dip.

Study on strata control by delay grouting in soft rock roadway

The properties of broken rock before and after grouting reinforcement are studied. Testing results show that grouting can raise the residual strength of broken rock, and the broken rockness by grouting can keep the steady supporting capacity within a relatively large deformation range. Revealing of the characteristics of stage deformation and damage process comes to the conclusion that the supporting of soft rock roadway should be analyzed in a dynamic view, and the grouting should be delayed at a proper occasion. Based on the above, the stepwise reinforcement technology characterized by immediate shotcreting, timely bolting and delay grouting is put forward and illustrated with a successful engineering practice.

Entry roof truss-bolt system test under the gob of contiguous seams

Roof bolt support system has been widely applied in the No.7, 9 seam in Caozhuang coal mine. However, it has not been able to be applied in the No.10-2 seam since the small interburden （2 m） between No.9 and No.10-2 seam. The No.9 and No.10-2 seams are contiguous seams. The No.9 seam has been mined out and the No.10-2 seam will be mined under the gob of the No.9 seam. The roof strata of the No.10-2 seam may have been weakened and fractured due to the shear failure caused by the No.9 seam mining activities. The steel beam sets spaced at 0.8 m have been used to support the entry of the No.10-2 seam. In order to speed up the advance rate and cut entry development cost, a test area, using roof bolt in conjunction with truss-system, was successfully conducted. This paper presents the support system design, application of designed system, and the test results. Test results provide a cheaper, quicker, and safer way to support entry for the No.10-2 seam.

“一巷多用”在易自燃高瓦斯突出煤层的实践

大兴矿投产以来，一直受瓦斯及煤层自然发火等难题困扰，尤以7煤层最为严重，严重制约着矿井安全生产。根据采空区“三带”理论，通过数据分析与计算，确定顶板道合理布置参数，并将其应用于S5—709工作面。通过实施，顶板道起到了瓦斯抽采和防治煤层自燃的双重作用，既提高了瓦斯抽采利用效率，又节省了其他工程投入，安全、经济效果明显，可作为同类条件工作面经验借鉴。