窄煤柱巷道非均匀变形机理及支护技术

Non-uniform deformation mechanism and support technology of narrow coal pillar roadway

为了解决窄煤柱巷道非均匀大变形控制难题,以丰汇煤矿窄煤柱巷道为工程背景,综合采用现场调研、室内实验、数值模拟和理论分析等方法,研究了不同煤柱尺寸影响下,采动巷道围岩应力与塑性区分布特征;分析了窄煤柱巷道变形破坏规律与采场覆岩结构运动特征,揭示了窄煤柱巷道非均匀变形机理,指出采动应力场叠加,支承压力大;覆岩结构非对称,偏载作用显著;煤柱尺寸小、强度低,难以为顶板提供有效支撑;支护方案对称布置,针对性差,是窄煤柱巷道产生非均匀变形的主要原因。基于窄煤柱巷道围岩控制难点,提出以"改变巷道区域支护方式、增加支护密度、破碎围岩注浆改性"为核心的差异化支护技术,加强对围岩局部大变形的控制,充分发挥围岩的自身承载能力;现场监测表明,窄煤柱巷道在服务期间围岩非均匀大变形得到有效控制,稳定性好;可为同类型巷道围岩的控制提供参考。

In order to solve the problem of non-uniform large deformation control of narrow pillar roadway, the narrow coal pillar roadway in Fenghui Coal Mine was used as the engineering background. The field survey,laboratory experi- ments, numerical simulation and theoretical analysis were used to study the stress and plastic zone distribution charac- teristics of surrounding rock of mining roadway under the influence of different coal pillar sizes. The deformation and failure laws of narrow coal pillar roadway and the movement characteristics of overlying strata structure were analyzed, and the mechanism of non-uniform deformation of narrow coal pillar roadway was revealed. Mining stress fields are su- perimposed, and results in a large abutment pressure;the structure of overlying strata is asymmetric,and causes a sig- nificant partial load effect;due to the small size and low strength of coal pillar, it is difficult to provide an effective sup- port for the roof; and the supporting scheme is symmetrically arranged, and poorly targeted ,which are the main reasons for the non-uniform deformation of narrow pillar roadway. Based on the diffieuh control characteristics of surrounding rock in narrow coal pillar roadway,the differential support technology with ＂the change of roadway support mode, theenhanced support density and grouting modification of broken surrounding rock＂ is proposed to strengthen the control of local large deformation of surrounding rock to give a full play to the carrying capacity of surrounding rocks. On-site monitoring results show that the non-uniform deformation of narrow coal pillar roadway during the service is effectively controlled, the surrounding rock is very stable. The differentiated support technology has a high reference value for the same type of roadway surrounding rock control.