深部软岩巷道围岩支护技术研究

Study on surrounding rock support technology of deep soft rock roadway

为有效解决深部软岩巷道围岩控制问题,针对信湖煤矿回风石门埋深大、应力高、围岩强度低的特点,在分析了信湖煤矿回风石门的围岩赋存条件、变形破坏特征以及原有支护方案已难以维持现掘巷道稳定的条件下,通过理论计算得到信湖煤矿回风石门围岩塑性区范围,从而提出了控制巷道围岩的基本理念:采用小承载体控制围岩破碎区的扩大,采用大承载体限制围岩塑性区的发展,2个承载结构共同维持巷道稳定,进而提出采用“混凝土喷射+注浆锚杆/锚索+普通锚杆/锚索”联合支护方案对新掘巷道进行支护,并结合FLAC^(3D)数值模拟及现场工业性试验对“混凝土喷射+注浆锚杆/锚索+普通锚杆/锚索”联合支护方案的合理性及可靠性进行验证。结果表明:信湖煤矿回风石门新掘巷道经“混凝土喷射+注浆锚杆/锚索+普通锚杆/锚索”联合支护方案支护后围岩表面变形趋于平稳,巷道顶板最大下沉量仅为36 mm,两帮移近量为67 mm,支护体与巷道围岩形成了稳定的复合承载结构,联合支护方案能够保持巷道的长期稳定,该联合支护方案可为其他类似深部软岩巷道支护提供一定参考。

In order to effectively solve the problem of surrounding rock control in deep soft rock roadways,in view of the characteristics of large burial depth,high stress and low surrounding rock strength of the air returning cross-cut of Xinhu Coal Mine,the surrounding rock occurrence conditions and factors of the return air crosscut in Xinhu coal mine were analyzed.Under the condition that the deformation and failure characteristics and the original support scheme have been difficult to maintain the stability of the existing roadway,the plastic zone of the surrounding rock of Xinhu coal mine was obtained by theoretical calculation,and the basic concept of controlling the surrounding rock of the roadway was put forward:the bearing body controls the expansion of the surrounding rock fracture zone,and the large bearing body was used to limit the development of the plastic zone of the surrounding rock.The two bearing structures jointly maintain the stability of the roadway,and then the joint support scheme of“anchor cable”supports the newly excavated roadway,and combined with Flac^(3D) nu⁃merical simulation and on-site industrial experiments,the joint support scheme of“concrete spray+grouting bolt/anchor cable+ordinary bolt/anchor cable”was supported,and reasonableness and reliability were verified.The results show that the deformation of the surround⁃ing rock surface tends to be stable after the support of the concrete support+grouting anchor/anchor cable+ordinary anchor/anchor cable in the new roadway section of the air returning cross-cut of Xinhucoal mine,the roof of the roadway.The maximum subsidence a⁃mount is only 36 mm,and the moving distance of the two groups is 67 mm.The supporting body and the surrounding rock of the roadway form a stable composite bearing structure.The joint support scheme can maintain the long-term stability of the roadway,and the joint support scheme can provide a certain reference for the support of other similar deep soft rock roadways.