软弱覆岩分层综放开采工作面“两带”发育高度研究
Research on the“two-zone” heights of soft stratum working face with slicing full-mechanized caving mining
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摘要: 水体下采煤突水溃砂事故是制约煤矿安全高效生产的主要因素之一,尤其对软岩矿区特厚煤 层高强度开采的威胁更为严重。 垮落带和导水裂隙带(合称“两带”)高度是水害预测预报的基本参 数,采用钻孔冲洗液漏失量观测、彩色钻孔电视观测及钻孔取芯的综合手段,通过地面钻孔对软弱覆岩 特厚煤层分层综放开采覆岩破坏“两带”发育高度进行现场观测,并利用离散元数值分析方法研究了 覆岩破坏裂隙场的变化特征。 研究结果表明,软弱覆岩特厚煤层分层综放开采时,上分层综放开采岩 层移动角约为75°,垮采比为5.60~5.62,裂采比为11.67~12.20;下分层综放开采垮采比为4.59~4.71,裂 采比为8.04~8.58;下分层采厚为上分层采厚的78.28% ~84.71%时,垮落带高度增大49.41% ~50.85%, 而垮采比减小16.19% ~18.33%,导水裂缝带高度增大21.72% ~25.38%,而裂采比减小29.67% ~ 34.10%。 本研究可对松散含水层下分层综放开采工作面水害预测预报及安全煤岩柱留设提供参考。Abstract: Waterandsandinrushisoneoftheprincipalfactorsthatrestrictsafeandeffectiveproduction ofminingunderwaterbody.Thethreattosoftstratamineswithextremelythickcoalseamisespecially moreserious.Cavingzoneandfissurezone(jointname“two-zone”)heightsarethebasicparametersof waterinrush prediction.This paper observes the “two-zone” heights of extra-thick coal seam with slicingfull-mechanized caving mining in soft stratum with comprehensive measures of flushing fluid leakage,colorboreholeTVandcore-drilling,andresearchesthefracturefieldcharacteristicsofoverburdenfailurethroughdiscreteelementnumericalmethod.Theresearchresultsareasfollows:underthe
conditionofextra-thickcoalseamwithslicingfull-mechanizedcavingmininginsoftstratum,thestratum movementangleoftopslicingworkingfaceisabout75°,theratiois5.60~5.62betweencavingzoneand miningheight,theratiois11.67~12.20betweenfissurezoneandminingheight;theratiois 4.59~4.71 betweencavingzoneandminingheight,theratiois8.04~8.58betweenfissurezoneandminingheight inthebottomslicingworkingface;theheightofcavingzoneincreasesby49.41% ~50.85% andthe heightoffissurezoneincreasesby21.72% ~25.38%,butthe ratiobetweencavingzoneandmining heightdecreasesby16.19% ~18.33%,theratiobetweenfissurezoneandminingheightdecreasesby 29.67% ~34.10% whentheminingheightofthebottomworkingfaceis78.28% ~84.71% ofthetop workingface.Theresearchresultscanprovidereferenceforwaterdamagepredictionandtheheightof safetycoalandrockpillarinslicingfull-mechanizedcavingminingfaceunderlooseaquifer.
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