柔模砼墙沿空留巷围岩变形规律及控制技术研究

Study on surrounding rock deformation law and control technology of flexible formwork concrete wall retaining roadway along goaf

为解决柔模砼墙沿空留巷围岩变形破坏严重的难题,以大柳塔煤矿52605工作面为工程地质背景,对沿空巷道围岩结构演化特性作了研究分析,提出采用无机注浆加固、加强顶帮结构及提高巷内高阻支护等综合方式确保沿空留巷稳定性,并进行了现场试验。结果表明:引起留巷围岩破坏的关键是上覆顶板下位关键岩层形成“悬臂梁结构”而将压力传递至巷道上;采用无机注浆加固材料能够改善巷道四周煤岩体的应力环境,形成再造承载层结构,提高留巷整体承载能力;滞后工作面180 m后留巷变形趋于稳定,顶板下沉最大246 mm、两帮收缩量最大315 mm、底鼓最大275 mm,能够控制住留巷破坏。为类似工程地质条件下的柔模墙沿空留巷的实施提供科学的技术指导。

In order to solve the problem of serious deformation and damage of the surrounding rock of the gob retaining roadway with flexible formwork concrete wall,taking the No.52605 working face of Daliuta Coal Mine as the engineering geological background,the evolution characteristics of the surrounding rock structure of the gob retaining roadway are studied and analyzed,and the comprehensive methods of inorganic grouting reinforcement,strengthening the roof structure and improving the high resistance support in the roadway are proposed to ensure the stability of the gob retaining roadway,and the field test is carried out.The results show that the key to the failure of the surrounding rock of the retained roadway is that the key rock layer under the overlying roof forms a“cantilever structure”and transmits the pressure to the roadway;The use of inorganic grouting reinforcement materials can improve the stress environment of coal and rock mass around the roadway,form a reconstructed bearing layer structure and improve the overall bearing capacity of the reserved roadway;After 180 m behind the working face,the deformation of the retaining roadway tends to be stable.The maximum roof subsidence is 246 mm,the maximum shrinkage of the two sides is 315 mm,and the maximum floor heave is 275 mm,which can control the damage of the retaining roadway.It provides scientific and technical guidance for the implementation of retaining roadway along goaf with flexible formwork wall under similar engineering geological conditions.