大倾角煤层走向长壁综放工作面顶板结构特征研究

发布时间：2018-11-01 19:02

【摘要】：大倾角煤层开采,在工作面顶板岩层中形成结构,工作面矿压显现是顶板结构失稳的外在表现。大倾角煤层走向长壁综放工作面顶板结构是一个复杂的空间结构,其结构特征及稳定性分析一直以来都是大倾角煤层走向长壁综放开采的一大难题。因此,研究大倾角煤层走向长壁综放工作面顶板结构特征,对完善大倾角煤层开采理论和岩层控制理论具有重要意义,对大倾角煤层走向长壁综放工作面支护结构设计、矿山压力控制、安全高效开采等工程实践具有指导作用。本文采用现场调研、数值模拟、物理相似模拟、理论分析和现场实测相结合的研究方法,对大倾角煤层走向长壁综放工作面顶板断裂特征、倾向砌体结构特征和覆岩承载拱结构特征进行了研究。研究表明:(1)大倾角煤层走向长壁综放工作面基本顶初次断裂裂隙形态为“X—O”型。虽然最终断裂形态与缓倾斜煤层的“O—X”型断裂形态相似,但由于岩层重力沿层面方向的分力较大,导致其断裂裂隙的产生及发展过程与缓倾斜煤层不同。工作面基本顶初次断裂后,沿采空区端基本顶的移动空间和受力状态与初次断裂之前不同,导致大倾角煤层走向长壁综放工作面基本顶周期断裂裂隙形态为“C—X”型。(2)大倾角煤层走向长壁综放工作面基本顶断裂成岩块后,沿工作面倾向易于形成砌体结构。倾向砌体结构承担了一部分基本顶岩层自重,减小了基本顶岩层对支架传递力的作用;倾向砌体结构的稳定性将直接影响工作面支架的受力状态。倾向砌体结构可能发生的失稳形式为滑落失稳和挤压变形失稳;最容易发生失稳的部位为工作面中上部。现场应采取加强对工作面中上部支架工作状态的监测以及提高支架支护强度,防止工作面中上部倾向砌体结构失稳。(3)大倾角煤层走向长壁综放工作面基本顶上覆岩层中形成承载拱结构。承载拱结构位于砌体结构的上部岩层中,沿工作面走向为对称平拱,沿工作面倾向为非对称斜拱。走向承载拱结构容易发生沿拱脚处的剪切破坏,倾向承载拱结构容易发生轴向压缩破坏。走向承载拱结构对整个工作面基本顶上覆岩层起控制作用,倾向承载拱结构失稳是由于走向承载拱结构的失稳而导致的。承载拱结构具有承担上覆岩层自重的能力,并对其下方工作面顶板及支架起保护作用,阻止了基本顶上覆岩层对其下方砌体结构和支架传递力的作用;当承载拱结构发生失稳时,将会给其下方砌体结构传递力的作用,并导致倾向砌体结构失稳,产生工作面来压现象。论文研究结果与枣泉煤矿120210综放工作面现场实测相吻合,为该矿后续工作面及回采巷道布置方式、回采工艺选择、设备配置提供依据,对该矿安全高效生产有着重要的指导意义。
[Abstract]:In the mining of large inclined coal seam, the structure is formed in the roof strata of the working face, and the appearance of mine pressure in the working face is the external manifestation of the instability of the roof structure. The roof structure of longwall fully mechanized caving face with large inclined seam is a complicated spatial structure, and its structural characteristics and stability analysis have always been a difficult problem in longwall fully mechanized caving mining. Therefore, it is of great significance to study the roof structure characteristics of longwall fully mechanized caving face with high inclined coal seam strike, which is of great significance to improve the mining theory and rock layer control theory, and to design the supporting structure of longwall fully mechanized caving face with high inclination seam strike. Mine pressure control, safe and efficient mining and other engineering practices have a guiding role. In this paper, based on field investigation, numerical simulation, physical similarity simulation, theoretical analysis and field measurement, the characteristics of roof fracture in longwall fully mechanized caving face with large inclined seam are studied. The characteristics of inclined masonry structure and overburden arch structure are studied. The results show that: (1) the primary fracture form of the top of the longwall fully mechanized caving face is "X-O" type. Although the final fracture form is similar to that of "O-X" type fracture of gently inclined coal seam, the formation and development process of fracture fissure is different from that of gently inclined coal seam due to the great force of gravity along the plane. After the first fracture of the basic top of the face, the moving space and the stress state along the end of the goaf are different from those before the initial fracture. As a result, the fracture form of long wall longwall fully mechanized caving face with large inclined seam is "C-X" type. (2) masonry structure is easy to be formed along the face after the basic roof fracture of longwall fully mechanized caving face with large inclined coal seam is formed. The inclined masonry structure bears part of the weight of the basic roof strata and reduces the effect of the basic top rock layer on the transfer force of the support; the stability of the inclined masonry structure will directly affect the bearing state of the support in the working face. The possible instability forms of inclined masonry structure are sliding instability and extrusion deformation instability, and the most vulnerable part is the middle and upper face. In the field, we should strengthen the monitoring of the working state of the upper and middle supports in the working face and improve the support strength. The upper and middle face inclined masonry structure is not stable. (3) the bearing arch structure is formed in the top overlying strata of the longwall fully mechanized caving face. The bearing arch structure is located in the upper rock layer of the masonry structure. The shear failure along the arch foot is easy to occur in the strike bearing arch structure, and the axial compression failure is easy to occur in the inclined bearing arch structure. The strike bearing arch structure controls the overlying strata on the basic roof of the whole working face, and the instability of the inclined bearing arch structure is caused by the instability of the strike bearing arch structure. The load-bearing arch structure has the ability to bear the weight of overburden strata, and plays a protective role on the roof and support of the working face below it, which prevents the basic roof overburden from acting on the masonry structure and the support transfer force under it. When the bearing arch structure is unstable, it will give the transfer force to the masonry structure below it, and will lead to the instability of the masonry structure, which will lead to the phenomenon of pressure coming from the working face. The results of this paper are in agreement with the field measurements of the 120210 fully mechanized caving face in Zaoquan Coal Mine, which provides the basis for the layout of the subsequent working face and the roadway, the selection of the stoping technology and the configuration of the equipment. It has important guiding significance for safe and efficient production of the mine.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD353

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