大断面综放沿空煤巷顶板破坏机制与锚索桁架控制

Failure mechanism and cable truss control of large-scale section gob-side entry roof with fully-mechanized caving

针对大断面综放沿空煤巷掘进过程中存在的支护难题,以王家岭煤矿20103区段运输平巷为工程背景,采用现场调研、数值模拟和井下试验等手段进行破坏机制与控制技术研究。结果表明:1)综放沿空煤巷顶板存在强烈的不对称下沉和水平挤压错动变形,煤柱侧顶板破碎严重,煤柱帮挤出变形显著;2)关键块回转运动引起沿空煤巷围岩性质和支承压力沿巷道中心轴两侧存在明显不对称性分布,其必然导致矿山压力显现的不对称性,关键块回转使得顶板岩层产生水平运动,进而导致岩层错动、滑移、膨胀形成挤压破碎带并压迫支护结构;3)关键块B的回转运动是综放沿空煤巷异常矿压显现的根本原因,顶板最大垂直位移位于巷道中心偏煤柱侧200~600mm范围内,最大水平位移量达250 mm,0水平位移点向实体煤侧偏移约0.9 m。提出了以不对称锚梁桁架为核心的综合控制系统,阐述了其减弱外部应力传递,加强煤柱侧顶板支护,适应顶板岩层水平运动及防治冒顶的原理。在上述研究基础上,结合王家岭地质生产条件进行支护参数设计,并进行现场应用。工程实践表明,该支护技术能够有效保证巷道顶板围岩稳定。

To solve the support problem of large-scale section gob-side entry with fully-mechanized caving in the process of excavating, with haulage roadway 20103 of Wangjialing coal area as the engi- neering background, the failure mechanism and control technology were analyzed through field obser- vation, theoretical analysis, numerical simulation, in-situ test and monitoring. The research results have shown that 1） Intense asymmetric sink and horizontal dislocation deformation occur in the roof, sur- rounding rock of roof over the pillar side is severely crushed, and coal pillar is severely damaged; 2） Asymmetric distribution of property and support stress of the surrounding rocks along the axis of road- way caused by rotation movement of the key blocks inevitably leads to asymmetric strata behaviors; the rotation of key block leads to the horizontal movement of roof, and further leads to the strong shear force and surrounding rock dislocation, embedding, expanding to extrusion fractures zones; 3） The rota- tion movement of key block B is the fundamental cause of abnormal strata pressure; the maximal verti- cal displacement exists in the middle of the roof 200-600 mm offset to the pillar, the maximal horizontal displacement is about 250 mm, and the location of 0 displacement is 0.9 m offset to the solid coal side. A comprehensive support system was proposed with asymmetric anchor truss rope at the core, and the operating principles of the system were further illustrated： it can weaken the delivery of outer pressure, strengthen the support strength of pillar side roof, adjust to the horizontal movement, and prevent seri- ous roof caving. Based on the study, the support parameters of test roadway was determined combing field production and geological conditions of Wangjialing Mine, and the support program was then put into field application. The field practice shows that the support technology can ensure the stability of the surrounding rock of the roof.