微波辐射下煤体孔裂隙结构演化特性

发布时间：2018-05-28 21:10

本文选题：微波 + 孔隙　；参考：《中国矿业大学学报》2017年06期

【摘要】：为了揭示微波能量对煤体孔裂隙结构的影响作用,设计了循环微波辐射实验,采用红外热成像、超声波探测、核磁共振和高精度X-CT扫描技术探讨了不同微波辐射时间下,煤体孔裂隙结构演化特性。结果表明:微波对煤体有开孔、疏孔和塌孔效应,其中开孔效应和疏孔效应占主导,微波辐射增大了煤体总孔体积和孔间连通性,使束缚流体孔隙率和自由流体孔隙率分别增大了30.3%和167.9%。微波辐射后,煤体内不同组分具有微波吸收异质性,煤体升温不均产生热应力,热应力撕裂原生裂隙并催生出新裂隙,从而导致NMR渗透率增大,超声波波速减小。煤样内部微裂隙增多并于辐射1.5min后转变为中、大裂隙,从而在煤体中形成裂隙网.
[Abstract]:In order to reveal the effect of microwave energy on the fracture structure of coal body, a circular microwave radiation experiment was designed. Infrared thermal imaging, ultrasonic detection, nuclear magnetic resonance (NMR) and high-precision X-CT scanning techniques were used to investigate different microwave radiation time. Evolution characteristics of pore and fissure structure in coal body. The results show that microwave has hole opening, pore thinning and caving effect on coal body, in which the hole opening effect and pore thinning effect are dominant, and microwave radiation increases the total pore volume and interpore connectivity of coal body. The porosity of bound fluid and free fluid increased by 30.3% and 167.9%, respectively. After microwave radiation, the different components of coal have the heterogeneity of microwave absorption, the thermal stress of coal is not uniform, the thermal stress tears the original fissure and creates a new fissure, which results in the increase of NMR permeability and the decrease of ultrasonic wave velocity. The microcracks in coal samples are increased and transformed into medium and large fractures after radiation of 1.5min, thus forming a fissure network in coal bodies.
【作者单位】：中国矿业大学煤矿瓦斯与火灾防治教育部重点实验室煤炭资源与安全开采国家重点实验室;
【基金】：国家重点研发计划项目(2016YFC0801402) 国家自然科学基金项目(51474211,51204174) 江苏高校优势学科建设工程资助项目
【分类号】：TD712

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