浅埋厚煤层连续采动下多关键层结构覆岩运移规律研究

Study on Overburden Migration Law of Multiple Key Layers in Shallow-buried and Thick Coal Seam

以鄂尔多斯转龙湾煤矿23203工作面开采为工程背景,采用连续非连续数值模拟和理论计算方法,对我国西北地区广泛分布的浅埋厚煤层连续采动下覆岩运移规律及矿压显现特征进行研究。结果表明:当埋深200m、厚度4.81 m的浅埋煤层一次采全高连续快速开采时,其基载比Jz>1且有3个关键层结构;连续采动作用下浅埋采场上覆岩层具有3种类型自稳结构,且各自稳结构的周期性破断相互影响,直接顶的第三次周期垮落形式存在“砌体梁”结构转化为“悬臂梁”结构的现象;多关键层结构工作面回采期间实测支架工作阻力值主要在11000~16500kN之间,平均值为14077.20kN,验证了数值模拟、理论计算及支架选型的合理性。研究成果可为浅埋厚煤层安全开采和支架选型提供重要科学依据。

Taking the mining of 23203working face of Zhuanlongwan Coal Mine in Ordos as the engineering background,the continuous-discontinuous numerical simulation and theoretical calculation method were used to study the migration law of overburden and the characteristics of mine pressure behavior under continuous mining of shallow-buried and thick coal seams widely distributed in Northwest China.The results are concluded as follows.Firstly,when a shallow-buried coal seam with a depth of 200mand a thickness of 4.81mis mined continuously and rapidly at full height,its base-load ratio Jzis greater than 1 and there are three key layer structures.Secondly,there are three types of self-stable structures in the overburden strata of shallow-buried stope under continuous mining,and the periodic fracture of each self-stable structure affects each other.The third periodic collapse form of the direct roof transforms the masonry beam structure into the cantilever beam structure.Thirdly,the measured working resistance value of support during the mining period of the multi-key layer structure working face is mainly between 11000kN and 16500kN,with an average value of 14077.20kN,which verifies the rationality of numerical simulation,theoretical calculation and support selection.The research results can provide important scientific basis for safe mining and support selection of shallow thick coal seam.