论煤层底板采动裂隙带的深度及分布特征

ON DEPTH OF FISSURED ZONE IN SEAM FLOOR RESULTED FROM COAL EXTRACTION AND ITS DISTRIBUTION CHARACTERISTICS

本文讨论了回采工作面底板的采动影响规律,提出了底板采动裂隙带最大深度的计算公式。根据现场实测资料及相似模型实验结果得出,在正常开采阶段,底板岩层处于采前压缩(增压)、采后膨胀(降压)及逐渐恢复的状态下;在永久煤柱的边缘区底板长期处于膨胀状态下,采动裂隙最发育,此处是承压水上回采工作面最易发生突水的部位。另外,本文采用弹塑性力学理论及实测资料分别得出了底板采动裂隙带最大深度的3种计算公式,并且应用现场实测资料分析论证了底板裂隙带的空间分布形态。

The paper discusses the rules of influence of mining on the floor of a work facc, and formulae for calculating the maximum depth of fissured zone induced by coal mining are proposed. Based on measured data from the site and results from simulation model tests in the laboratory, it is found that in the normal mining period, the floor strata are compressed (increased pressure) before mining, and expanded (decreased pressure) after mining, and resume gradually to original status; and that on the fringe of permanent coal pillar, the floor is in expansion status for long periods and fissures resulted from mining are well developed. This is the location where water-inrush is most likely to occur in face on confined aquifer. In addition,three formulae are established to calculate the maximum depth of fissured zone in the floor due to mining based on elastoplastic theory and measured data. And spatial distribution pattern of fissured zone in the floor is analyzed and proved by data from site measurement.