深部复合顶板巷道变形破坏特征及支护技术

Deformation and failure characteristics and support technology of deep roadway with composite roof

针对深部复合顶板巷道易冒顶、大变形、难支护等问题,以晋城蓝焰煤业股份有限公司成庄矿53182巷为研究对象,分析了深部复合顶板巷道变形破坏特征:顶板变形以浅部离层为主,离层主要出现在不同岩层分界面处;顶角和顶板两侧锚杆主要在煤岩分界面处出现明显剪切变形,顶板中部锚杆在弱胶结岩层和锚杆锚固段与自由段分界面处剪切变形较大;顶板岩层经历了巷道初掘时原岩状态及巷道掘出后稳定状态、临界失稳状态、失稳状态的过程。数值模拟结果表明:随着锚杆预紧力的增加,顶板塑性区范围和垂直位移明显减小,锚杆对顶板离层和下沉的抑制作用更好;高预应力锚杆发挥了主动支护作用,同时大幅度提高了围岩的自承载能力。提出了高预应力长短锚索相结合、配合钢筋网和W钢带的深部复合顶板巷道支护对策,可大幅度提高复合顶板支护刚度,对顶板下沉和离层形成约束,增强复合顶板岩层整体稳定性。工程实践表明:高预应力支护有效控制了复合顶板离层和下沉,浅部离层值控制在30mm以内,深部离层值控制在10mm以内,两帮移近量控制在80mm以内,顶板下沉量控制在43mm以内,巷道围岩稳定性、完整性良好。

In view of problems of deep roadway with composite roof,such as easily roof falling,large deformation and difficult support,taking 53182 roadway of Chengzhuang Coal Mine of Jincheng Blue Flame Coal Industry Co.,Ltd.as research object,deformation and failure characteristics of deep roadway with composite roof were analyzed.It is found that roof deformation is dominated by shallow separation layer,which mainly occurs at interface of different rock strata.Shear deformation of bolts in top corner and two sides of roof occurs mainly at coal-rock interface,and shear deformation of bolts in the middle of roof is relatively large at weakly cemented strata and interface between anchor section and free section.Roof strata experiences processes of original rock state during initial excavation of roadway,and stable state,critical instability state and instability state after roadway excavation.The numerical simulation results show that with the increase of bolt preload,plastic zone range and vertical displacement of roof decrease obviously,which indicate bolt has better inhibiting effect on roof separation and subsidence.High prestressed bolt plays an active support role and greatly improves self-bearing capacity of surrounding rock.Support countermeasures of deep roadway with composite roof with high prestressed long and short anchor cables combined with steel mesh and W steel strip were put forward,which could greatly improve support stiffness of composite roof,form constraints on roof subsidence and separation,and enhance overall stability of composite roof strata.The engineering practice shows that high prestressed support effectively controls separation and subsidence of composite roof.Shallow separation value is controlled within 30 mm,deep separation value is controlled within 10 mm,two sides displacement is controlled within 80 mm,and roof subsidence is controlled within 43 mm.The above values indicate stability and integrity of surrounding rock.