摘要
开展火烧岩烧变温度的识别对于火烧岩的形成及演化具有重要的指导意义。基于热Kaiser效应,通过火烧岩在热处理过程中的声发射累计能量以及参数RA(上升时间/振幅)和AF(平均频率)值的变化,对陕北神木张家峁火烧岩的阈值温度进行了预测。结果表明:火烧岩热声发射特征能有效识别火烧岩烧变温度,与火烧岩经历温度的岩相学分析基本一致;研究区火烧岩存在显著的地层烧变温度梯度,第1—第5层岩石烧变阈值温度逐渐升高,对于第6层和第7层岩石,最高温度超过700℃,对于第8层岩石,阈值温度为245℃;当热处理温度较低时,岩石内部沿晶拉张裂纹发育,超过600℃后,穿晶剪切裂纹所占比例开始增加,声发射信号出现二次增长,同时声发射出现平静期,累计能量曲线出现多个平台。火烧岩烧变温度的识别,对于煤矿防治水及围岩稳定性研究等具有重要的现实意义。
The identification of the burning temperature of burnt rocks has important guiding significance for the formation and evolution of burnt rocks.Based on the thermal Kaiser effect,the threshold temperature of burnt rock in Zhangjiamao,Shenmu,Northern Shaanxi Province is predicted through the acoustic emission(AE) acumulated energy and the changes of parameters RA(rise time/amplitude) and AF(average frequency) during heat treatment.The results show that the thermoacoustic emission characteristics of burnt rocks can effectively identify the burning temperature of burnt rocks,and it is basically consistent with the petrographic analysis of the temperature experienced by the burnt rocks.There is a significant formation burning temperature gradient in the burnt rocks in the study area.For the rocks in the first to the fifth layers,the burning threshold temperature increases gradually;for the sixth to the seventh layers of rock,the maximum temperature exceeds 700℃;for the eighth layer of rock,the threshold temperature is 245℃.When the heat treatment temperature is low,the intergranular tensile cracks develop in the rock.When the temperature exceeds 600℃,the proportion of transgranular shear cracks begins to increase,and the AE signal increases twice.At the same time,there is a quiet period of AE,and there are multiple platforms in the cumulative energy curve.The identification and zoning of burning temperature of burnt rocks,it has important practical significance for water control of coal mine and stability of surrounding rock.
作者
孙强
王少飞
葛振龙
魏少妮
丁晓英
SUN Qiang;WANG Shaofei;GE Zhenlong;WEI Shaoni;DING Xiaoying(College of Geology and Environment,Xi’an University of Science and Technology,Xi’an 710054,China;Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation,Xi’an 710054,China;Geological Research Institute for Coal Green Mining,Xi’an University of Science and Technology,Xi’an 710054,China;Key Laboratory of Coal Resources Exploration and Comprehensive Utilization,Ministry of Natural Resources,Xi’an 710021,China)
出处
《煤田地质与勘探》
CAS
CSCD
北大核心
2022年第5期82-88,共7页
Coal Geology & Exploration
基金
国家自然科学基金项目(41972288)
自然资源部煤炭资源勘查与综合利用重点实验室开放研究课题(KF2021-7)
陕西省煤炭绿色开发地质保障重点实验室专项基金项目(DZBZ2021Z-06)。
