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节理化脆性特厚煤层巷道大变形机理及控制技术

Large-deformation mechanism and control technology of roadway injointed and brittle and extremely thick coal seam

  • 摘要: 针对潞新矿区脆性特厚煤层内巷道强矿压显现、大变形等难题,采用理论分析、数值模拟和现场试验等方法进行了巷道大变形机理和控制方法研究。结果表明:巷道在冲击性载荷影响下的大变形机理为强卸载和冲击性载荷双重作用引起煤层的似层裂、劈裂并不断扩展导致剪胀变形;离散元动态模拟显示动载荷强度对变形的影响最大,动载荷强度达到15 MPa,顶板离层严重,承载结构失效,超过25 MPa,顶板失稳;提出以提高支护材料的延伸率和冲击韧性以及增大支护构件的护表面积和刚度为核心的强护表高韧性整体支护法,经现场试验该支护方法成功将顶板及两帮变形控制在240 mm和130 mm;动载荷持续影响下顶板锚索受力呈现波动特征,两帮锚杆受力受开挖与节理方向关系和煤层倾角影响而呈现不同变化规律。

     

    Abstract: Aiming at strong mining pressure behaviors and large deformation of the extremely thick and brittle coal seam in Luxin Mining Area, comprehensive method including theoretical analysis, numerical simulation and industrial test were adopted to research the deforming mechanism and controlling method.The large deformation mechanism of roadway under dynamic load were the spallation, cleavage of coal seam and the dilatancy induced by the synthetic action of strong unloading and dynamic load. DEM dynamic modelling showed that dynamic load intensity played the most important role in the roadway deformation,large roof separation appeared and load bearing structure failed when dynamic load reached 15 MPa, while in excess of 25 MPa roof was instable. The integral support method of intensive surface protecting and high impact toughness was put forward, whose core was the ductility, impact toughness of supporting materials and intensive surface protecting of support components,underground test showed that roadway deformation was safely controlled to 240 mm roof convergence and 130 mm two-sides displacement. Loads of roof cables were fluctuant and loading variation rules of bolts in two sides were different in case of the relation of joints and excavating orientation and coal seam dip.

     

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