小纪汗煤矿工作面顶板破断结构对巷道矿压影响规律研究

摘要

Under the conditions of brittle coal and thick main roof,there are a large deformation of roadway and failure of support structure during secondary mining at western mining area in China.Using the method of theoretical analysis and field measurement,the breaking structure of main roof on roadway top and the law of roadway deformation were studied.Taking the key lateral breaking block of main roof as a research target,the second time stress distribution of the roadway surrounding rock caused by the double arch structure of the secondary mining which is brought by the cantilever beam structure double arch structure of the first mining was analyzed in detail.The quantitative relationship between main roof breaking length and coal seam thickness,strata characteristics,overlying load,coal pillar parameters and the stress concentration was given.The expressions of coal pillar top load under different breaking structures were obtained.Results show that the "double arch" hinged structure formed by the breaking of main in the front of the working face is the main reason that causes the severe pressure of this kind of roadway.The irrationalcoal pillar width will induce the stress function that leading to the overall deformation of the roadway and the failure of supporting structure.The results of the study have a good guiding significance for the surrounding rock control and the reasonable coal pillar size design in a similar engineering geological condition.%针对我国西部矿区脆性煤体上覆厚层基本顶条件下二次采动时巷道围岩整体变形大与支护结构失效的工程难题,运用理论分析和现场实测的研究方法,对巷道上方基本顶破断结构及由此带来的巷道变形规律进行了研究.以工作面基本顶侧向破断的关键块为研究对象,详细分析了巷道上方基本顶结构由一次采动时的固支悬臂梁结构转变为二次采动时的双拱结构而带来的煤柱中的应力演化规律,给出了基本顶侧向破断长度与煤层厚度、基本顶力学特性、上覆载荷和区段煤柱参数的量化关系式,得出了不同破断结构下煤柱载荷的表达式.结果表明:工作面超前段基本顶侧向断裂形成的“双拱”铰接结构是造成该类巷道矿压显现剧烈的主要控制原因,不合理的区段煤柱宽度会诱发叠加应力作用,导致巷道整体变形与支护结构失效.研究结果可为相似工程条件下巷道围岩控制和合理区段煤柱的留设提供借鉴.