煤矿井下自燃危险区域无线信号衰减规律研究

发布时间：2018-11-24 18:54

【摘要】：掌握煤自燃危险区域特征信息是防治矿井内因火灾的重要前提。目前常用的监测方法如安全监控、束管监测、人工检测等在监测区域、监测精度等方面存在不足,本论文以近年来新兴的矿井无线通信技术为研究对象,分别对工作面沿空侧、密闭区域及煤岩体介质中这三大区域的无线通信性能开展研究,对煤矿井下无线通信技术开发具有重要指导意义。文章首先分析了采空区、密闭区域及沿空巷道三种煤自燃危险区域无线通信环境及传输损耗因素,得到了煤岩体介质属于有损耗介质,电性参数和通信频率是影响无线信号传输的主要因素;沿空巷道属于受限空间,电磁信号传输质量与围岩电参数、横截面尺寸、巷道壁倾斜和粗糙程度有关,且受电磁干扰的影响较大。建立了煤岩体介质及沿空巷道的无线通信衰减模型,理论计算得到在煤岩体中趋肤深度大于5米时通信频段必须小于1MHz,沿空巷道中无线通信的截止频率为291MHz,结合井下电磁干扰统计,沿空巷道无线通信的优选频率必须大于500MHz。采用MATLAB通信软件,对煤岩体介质及沿空巷道的通信性能进行仿真,得到了不同通信频率的衰减系数及有效通信距离之间的定量关系,拟合得出衰减系数及通信距离与频率成二次函数关系。在龙固煤矿2303工作面沿空巷道及地面堆煤场进行应用,测试了169MHz、433MHz、900MHz、2.4GHz四种频率的传输距离和衰减特性,验证了理论计算的准确性。
[Abstract]:It is an important prerequisite to prevent and cure mine internal fire by mastering the characteristic information of the dangerous area of coal spontaneous combustion. At present, the commonly used monitoring methods, such as safety monitoring, tube monitoring, manual detection and so on, are insufficient in monitoring area, monitoring accuracy and so on. In this paper, the emerging wireless communication technology in coal mine is taken as the research object, and the face side along the gob is studied separately. The research on the wireless communication performance of the three regions in the closed area and in the coal and rock mass media is of great significance to the development of wireless communication technology in underground coal mines. This paper first analyzes the wireless communication environment and transmission loss factors in the three dangerous areas of coal spontaneous combustion in goaf, closed area and roadway along the goaf, and obtains that the coal and rock mass media belong to the lossy medium. Electrical parameters and communication frequency are the main factors affecting wireless signal transmission. The transmission quality of electromagnetic signal is related to the electrical parameters of surrounding rock, the size of cross section, the inclination of tunnel wall and the degree of roughness, and is greatly affected by electromagnetic interference. The wireless communication attenuation model of coal and rock mass media and goaf roadway is established. The theoretical calculation shows that the communication frequency band must be less than 1 MHz when the skin depth of coal and rock mass is more than 5 m, and the cut-off frequency of wireless communication in goaf roadway is 291 MHz. According to the statistics of underground electromagnetic interference, the optimal selection frequency of wireless communication along goaf must be more than 500 MHz. Using MATLAB communication software, the communication performance of coal and rock mass media and roadway along goaf is simulated, and the quantitative relationship between attenuation coefficient of different communication frequency and effective communication distance is obtained. The quadratic function of attenuation coefficient, communication distance and frequency is obtained by fitting. The transmission distance and attenuation characteristics of four frequencies of 169MHz ~ 433MHz ~ 900MHz ~ 2. 4GHz have been tested in the goaf roadway and ground heap coal yard of 2303 face of Longgu Coal Mine. The accuracy of theoretical calculation has been verified.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD752.2

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