深厚煤层开采底板变形特征的光纤监测研究

煤层工作面采动会引起采场底板应力场重新分布,发生煤岩体的变形与破坏,准确掌握其时空发育特征对底板突水预测具有十分重要的意义。为了探究大埋深特厚煤层开采底板岩层裂隙场的发育规律,依托准格尔煤田某矿开采工作面,采用井孔光纤应变测试技术开展室内岩石压裂测试并实施底板监测,获得了大采高底板下不同深度岩层随工作面推进的应变变化曲线及特征。结果表明:光纤监测技术可有效捕捉深部煤炭开采底板岩层破坏特征,特别反映出在垂向分布上通过应变与岩层对应关系可得到底板裂隙场发育具有一定的分层性,其分布主要受地层结构影响,并且破坏优先发生于软弱岩层和软、硬岩层交界面附近。且通过1#、2#钻孔应变特征综合分析61101工作面受采动影响底板最大裂隙发育深度为21.5 m。

Optical Fiber Monitoring Study on Characteristics of Deformation in Floor of Deep and Thick Coal Seam During Mining

Affected by the mining of coal seam, the stress field of the floor will redistribute, and the deformation and destroy will produce. It is very important to master the space-time development characteristic of the floor rock for prediction the water inrush from seam floor. To explore the development and distribution features of fracture field of rock mass in mining floor of thick coal seam under the condition of deep layer covering, the borehole optical fiber strain testing technology is adopted to make rock crushing indoor and practical measure research for working face based on one mining working face in Zhungeer coal field, and the strain change curve and distribution features of rocks with different depths during advancing of working face are attained under large mining height base plate. The testing results show that the optical fiber monitoring technology can capture fine features of floor deformation and destroy in deep coal mining effectively. Especially in vertical distribution, the development of floor fracture field has certain laminarity through analyzing correspondence of strain and rock stratum, and its distribution is affected mainly by the stratum structure. The destroy development is a priority in softness stratum or the interface nearby of soft and hard rock stratum. The maximum depth of fracture is 21.5 m in the 61101 working face through monitoring and comprehensive analysis from the data of 1# and 2# drill.