为解决“三下”采煤规程中近距离煤层组综合采高MZ计算公式在上下煤层间距较大时计算结果失真问题,基于开采沉陷规律和时间效应,研究并提出了2层及以上近距离煤层组(群)开采时“两带”高度预计方法,即导水裂缝带和垮落带.研究结果表明:根据煤层采高M、垮落带高度Hk和煤层间距h,近距离煤层组又可划分为较近距离煤层组(M＜h≤Hk)和极近距离煤层组(0≤h≤M);近距离煤层组(群)折算采高MZS为将采煤层采高加上由已采煤层和煤层间距折算的采高,极近距离煤层组还需考虑时间因素;基于MZS提出了“判别煤层组类型—计算折算采高—确定‘两带’高度”三步法的近距离煤层组(群)开采“两带”高度预计方法及预计公式.实际工程应用验证该方法更为合理、有效,可为水体下多煤层安全高效开采提供了技术支撑.%In order to solve the inaccurate problems of calculation results of combined mining height (MZ) formula derived from'mining regulations under water,railway and buildings',to contiguous seams group when the distance between the upper and lower coal seam is large,based on the mining-induced subsidence law and time effect,the authors put forward prediction method of height of "two zones" (caving zone and fractured zone) to two or more layers of contiguous coal seams.The results show that,according to the mining height (M),caving zone's height (Hk) and interlayer's distance(h),the contiguous coal seams group can be divided into close contiguous coal seams (M＜h ≤ Hk) and ultra contiguous coal seams (0 ≤ h ≤ M).The converted mining height (MZS) of contiguous coal seams group,is composed by the coal seam mining height added the conversion mining height calculated by its upper seam thickness and the seams distance,and time factor must be considered in this situations.The estimating method and formula of the heights of "two zones" are proposed based on MZS with three steps,firstly deciding the type of coal seam group,secondly calculating converted mining height,lastly estimating the heights of "two zones" of contiguous coal seams.The application practice verifies that this new method is more reasonable and effective and will contribute to the enhancement of mining safety and efficiency under water bodies.
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