任艳芳. 浅埋深工作面覆岩“悬臂梁-铰接岩梁”结构的提出与验证[J]. 煤炭学报, 2019, 44(S1): 1-8. DOI: 10.13225/j.cnki.jccs.2019.0099
引用本文: 任艳芳. 浅埋深工作面覆岩“悬臂梁-铰接岩梁”结构的提出与验证[J]. 煤炭学报, 2019, 44(S1): 1-8. DOI: 10.13225/j.cnki.jccs.2019.0099
REN Yanfang. Presentation and verification of “cantilever beam-articulated rock beam” composite structure in shallow buried working face[J]. Journal of China Coal Society, 2019, 44(S1): 1-8. DOI: 10.13225/j.cnki.jccs.2019.0099
Citation: REN Yanfang. Presentation and verification of “cantilever beam-articulated rock beam” composite structure in shallow buried working face[J]. Journal of China Coal Society, 2019, 44(S1): 1-8. DOI: 10.13225/j.cnki.jccs.2019.0099

浅埋深工作面覆岩“悬臂梁-铰接岩梁”结构的提出与验证

Presentation and verification of “cantilever beam-articulated rock beam” composite structure in shallow buried working face

  • 摘要: 浅埋深煤层开采后,受其特殊的地质赋存条件影响,覆岩中无法形成完整“三带”,所形成的承载结构也不能稳定存在,结构失稳后形成浅埋深煤层特殊的顶板来压特征。以浅埋煤层特殊的顶板破断及运动特征为基础,通过相似模拟和离散元模拟2种方法探索浅埋深长壁工作面岩层破断运动特征及覆岩结构形式,提出浅埋深工作面覆岩中“悬臂梁-铰接岩梁”组合岩层结构,其中,基本顶破断后形成铰接岩梁结构,承担其自身及“悬臂梁”下方软弱岩层载荷,并受悬臂梁断裂下沉载荷影响,其失稳载荷通过直接顶作用于工作面支架上; 基本顶上部岩层形成悬臂梁结构,承担其自身及覆盖松散层载荷,其断裂下沉步距要大于“铰接岩梁”失稳步距; 两级岩层结构所处层位不同,其形成与失稳活动共同影响回采空间。结合典型浅埋深工作面的矿压及地表下沉规律实测结果,对所提出的“悬臂梁-铰接岩梁”组合结构进行了验证。通过对“悬臂梁-铰接岩梁”两级岩层结构受力状态进行分析,得到“悬臂梁”断裂下沉而引起“铰接岩梁”结构在煤壁处出现滑落失稳是造成浅埋深长壁工作面顶板沿煤壁切落、形成压架事故的根本原因,是影响工作面安全回采的顶板载荷主要来源,并以此为基础提出浅埋深条件下工作面切顶灾害的控制原则。

     

    Abstract: Affected by its special geological occurrence conditions, it is impossible to form complete overburden rock "three zones" in shallow coal seam mining and the bearing structure formed cannot exist stably.After a period of struc-tural instability, the special roof weighting characteristics of shallow-buried deep seam are formed.Based on the special roof breaking and movement characteristics of shallow coal seam, this paper explores the rock breaking movement characteristics and overburden structure form of shallow longwall working face through similarity simulation and dis-crete element simulation, and puts forward the composite rock structure of "cantilever beam-articulated rock beam" in the overburden of shallow working face, in which the articulated rock beam structure is formed by broken main roof rock, and bears the load of itself and weak rock layer under "cantilever beam".Besides, the articulated rock beam is also affected by the cantilever beam fracture subsidence load, and its instability load acts on the support of the working face through the direct roof.The cantilever beam structure is formed by the upper rock strata above main roof, which bears the load of itself and covers the loose layer, and its breaking subsidence step is larger than the "articulated rock beam" instability step.The two-stage rock stratum structure locates in different strata, their formation and instability are different and affect the mining space together.Combining with the measured results of ground pressure and ground subsidence law of typical shallow working face, the composite structure of cantilever beam and articulated rock beam is validated.Through the stress state analysis of the two-stage rock stratum structure of "cantilever beam-articulated rock beam", it is concluded that the sliding and instability of the "articulated rock beam" structure caused by the fracture and subsidence of the "cantilever beam" is the root cause of the roof cutting along the coal wall in the shallow-buried longwall face, and also the main source of roof load affecting the safe mining.Therefore, the control principle of roof cutting disaster in Shallow-buried working face is put forward.

     

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