煤体破裂度演化规律的细观力学描述研究

发布时间：2018-03-15 10:20

本文选题：原煤试件　切入点：声发射　出处：《安徽理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：为了深入研究煤体的破裂规律及现象,本篇文章通过对谢一矿原煤进行研究分析,运用理论分析、实验室实验以及数值模拟等相结合的方式分析煤的破裂程度变化规律。对原煤试件进行单轴压缩实验,分析多组原煤试件在单轴压缩的不同阶段的力学特征,得出相似的破坏规律,按照此规律将原煤的破坏过程分成四个阶段。接着,原煤试件声发射振铃计数变化和其应力时间变化图像基本反映了其内部破裂程度的变化。从声发射的能量特性图上可以看出其图形的变化趋势与煤体的应力时间图像保持着基本吻合。经过分析可以得到煤体的内部的破裂程度从压密阶段的微小到弹性阶段的稳定而又缓慢的增大,然后再到塑性阶段的剧烈增加,以及到最后破坏阶段的最大。并用RFPA数值模拟得到了验证。对原煤试件表面进行数字散斑相关法的相关处理,通过综合分析原煤试件表面位移场在与之对应的原煤试件不同破坏阶段的变化趋势,其破裂程度从压密阶段的微小到弹性阶段的稳定而又缓慢的增大,然后再到塑性阶段的缓慢的增大,以及到最后破坏阶段的最大。对应相同阶段煤体的内部和表面的破裂程度的变化情况,得到煤体在声发射的快速增长阶段的后期发生外部破裂。研究原煤的破裂度的演化规律对井下煤体破坏有着重要的意义。综合煤体内部破裂程度和外部破裂程度,得到煤体在声发射现象的具体阶段发生破裂,可以运用声发射检测技术对井下进行实时监测,防止煤体突然破裂带来的危害,尤其对井下的相关动力灾害防治有着及其重要的研究价值。
[Abstract]:In order to study the fracture law and phenomenon of coal body in depth, this paper analyzes the raw coal in Xieyi Coal Mine and makes use of the theory analysis. Laboratory experiments and numerical simulation are combined to analyze the variation of coal fracture degree. Uniaxial compression experiments are carried out to analyze the mechanical characteristics of multiple groups of raw coal specimens in different stages of uniaxial compression. A similar failure law is obtained, according to which the failure process of raw coal is divided into four stages. The changes of acoustic emission ring count and stress time of raw coal samples basically reflect the change of internal rupture degree. From the energy characteristic diagram of acoustic emission, we can see the changing trend of the pattern and the stress time of coal body. The images are basically consistent. The analysis shows that the degree of internal rupture of the coal body increases steadily and slowly from the small to the elastic stage of the compaction stage. Then the plastic stage increases sharply, and the final failure stage reaches the maximum. The RFPA numerical simulation is used to verify that the surface of the raw coal sample is treated by the digital speckle correlation method. By synthetically analyzing the change trend of the surface displacement field of the raw coal specimen in different failure stages of the corresponding raw coal specimen, its rupture degree increases steadily and slowly from the small stage of compaction stage to the elastic stage. Then to the slow increase in the plastic stage, and to the maximum in the final stage of failure, corresponding to the change in the degree of rupture inside and on the surface of the coal body at the same stage, It is obtained that the external fracture occurs in the late stage of the rapid growth stage of acoustic emission. It is important to study the evolution law of the fracture degree of the raw coal for the destruction of the underground coal body. It is obtained that the coal body ruptures in the concrete stage of acoustic emission phenomenon, and the acoustic emission detection technology can be used to monitor the underground in real time to prevent the harm caused by the sudden rupture of the coal body. Especially for underground power disaster prevention and control has important research value.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD313

【参考文献】