厚煤层柔模混凝土墙沿空巷道支护技术研究

Gob-side roadway support in thick seam using flexible formwork concrete wall

柔模混凝土墙沿空留巷技术作为无煤柱开采的一种,现已被应用于我国神东矿区多个煤矿。为解决在留巷复用过程中沿空巷道围岩结构稳定性差、变形剧烈、支护难度大的难题,以大柳塔煤矿52605柔模混凝土墙沿空留巷工作面为工程背景,采用理论分析、数值模拟和现场实测相结合的研究方法,研究了柔模混凝土墙沿空巷道的围岩变形特征,建立柔模混凝土墙沿空巷道围岩结构力学模型,得到从巷道掘进阶段至巷道复用阶段沿空巷道全生命使用周期的应力演化规律,并根据巷道不同的使用阶段提出了对应的支护方案。研究结果表明:上覆岩层作用力直接作用在直接顶与混凝土墙岩层接触位置,有利于侧向支承压力传递,巷道围岩变形较大;二次采动超前支承压力导致留巷段前方顶板发生塑性破坏,塑性破坏与底板塑性区联通,将加剧煤壁侧的破坏;现场工程实践表明对沿空巷道进行合理分时分区支护,可改善应力环境,有效控制围岩变形。

As a kind of non-coal pillar mining technology,flexible formwork concrete wall for gob-side entry retaining has been applied in many coal mines in Shendong mining area of China.In order to solve the problem of poor stability,drastic deformation and difficult support of the surrounding rock during reuse of gob-side entry,taking the No.52606 gob-side entry retaining working face with flexible formwork concrete wall in Daliuta Coal Mine as the background,theoretical analysis,numerical simulation and on-site measurements were carried to study the surrounding rock deformation characteristics of the flexible formwork concrete wall gob-side roadway,set up surrounding rock mechanical model for gob-side roadway with the flexible concrete wall,and obtain the stress evolution law for the whole life cycle of the roadway from the tunneling stage to the reuse stage,thus to propose the corresponding support schemes according to different working stages of the roadway.The research results show that:the overlying strata force acts directly on the connecting part of immediate roof and concrete wall rock layer,which leads to the transfer of lateral abutment pressure,and larger deformation of the roadway surrounding rock.The advance abutment pressure of secondary mining produced roof plastic damage in the front of the retained roadway.The plastic damage is connected with floor plastic zone,which will intensify the destruction of sides of the coal wall.The on-site engineering practice shows that,supporting at specific time and zone along gob-side roadway can improve the stress environment and effectively control the deformation of surrounding rock.