Research & Application Of Monitoring Technology For Goaf Temperature Field Of Coal-mines Based On FBG

In recent years, spontaneous combustion of goaf has been one of the major disasters in the coal-mines. Once combusted, it brings great harm to the staff and the equipments, which not only affects the normal production in the face, but also threatens the other faces. More seriously, it's very blind when putting out a fire because of no accurate positioning measures to fire source, which brings about huge economic loss, easily up to 10 millions. Thus, there is a great practical significance to research the monitoring technology for goaf temperature field, protecting the safe production in the coal-mines and reducing the cost of fire prevention and fire fighting.Recently, the measures to detect temperature in the coal-mines are mainly realized by electric instruments, such as temperature sensing cable, integrated temperature sensor chip and so on. This kind of sensor is charged by electricity, and has lots of weakness in the complex environment of coal-mines, like potential safety hazard, big detecting error, weak positioning function. Besides, it can't realize long-term continuous detection.This paper studies a kind of monitoring technology for goaf temperature field of coal-mines based on fiber Bragg gratings, which can precisely measure the temperature of detected spots by forming distributed monitoring field in goaf. In addition, fiber grating sensors have the following advantages, including small size, essential safety, electrical isolation, anti-electromagnetic interference, high accuracy, strong reliability, fast sensitivity, good adaptability to environment. Even more, it's suitable for remote sensing detection and can realize multipoint and more than one field real-time passive measuring. Consequently, it has wide application prospect to use fiber grating sensors in the goaf of coal-mines, monitoring the temperature field.This article presents the development situation of monitoring technology for goaf temperature field of coal-mines and designs the monitoring technology for goaf temperature field based on the monitoring needs of coal-mines industry. The main research contents and results are as follows:1 FBG temperature sensor used in coal-mines is researched & designed, including FBG temperature probe and package structure of FBG sensor. FBG temperature sensor gets good temperature sensitivity and high strength of extension. On this basis, the manufacturing method or technology of temperature-detecting cable is formed.2 Monitoring system of goaf temperature field is designed, and the system units are designed & selected. Meanwhile, the layout project & the engineering implementation scheme of temperature cable are researched and formed.3 Spacial interpolation algorithms are studied, especially the Kriging, realizing spacial interpolation for goaf temperature field by programming and obtaining a more comprehensive goaf temperature field.4 The application to monitor goaf temperature field is realized based on the designed monitoring technology. The goaf temperature field is basically detected when the monitoring technology is used in the working face?020210 of Yang Changwan coal-mine in Ningxia. The result shows that this monitoring technology has high accuracy and good sensitivity. Meanwhile, the rules of goaf temperature field are obtained by fitting and analyzing the measured datas.