Coal mine rock burst and coal and gas outburst perception alarm method based on thermal infrared image

According to the disaster mechanism of rock burst, and coal and gas outburst is not completely clear, and they still occasionally occur, which seriously threatens the safety of coal mine production. Combined with the temperature and velocity characteristics of a large number of coal rocks thrown out when disaster occurs, which are different from the normal working conditions of mining face and roadway space, a perception alarm method of coal mine rock burst, and coal and gas outburst based on thermal infrared image is proposed. First, the infrared thermal imager is placed on the top of the roadway, the roadway wall and the hydraulic support of the working face in the coal mine to collect the thermal infrared video images of the working face and the roadway space in real time. Second, the temperature of object in the monitoring area is monitored and identified whether it is in the set temperature range (30 ℃≤T≤150 ℃). Third, when the temperature of the object is monitored by the infrared thermal imager at the end of excavation roadway, the entrance of excavation roadway, the middle of excavation roadway, mining face, the entrance of inlet air roadway, the middle of inlet air roadway, the entrance of return air roadway, the middle of return air roadway, the main transportation roadway, the auxiliary transportation roadway and other locations, it can monitor and identify whether the moving speed of the object in the set temperature range is in the set speed range (v > 13 m/s). Fourth, when it is in the set speed range, the methane sensor is used to monitor whether the environmental methane concentration in the monitoring area rises rapidly in multiple locations. Fifth, when methane concentration increases significantly at different locations such as working face, return air roadway, inlet air roadway and total return air roadway, the alarm is set for coal and gas outburst, otherwise, the alarm is set for rock burst. A method to determine the best dip angle of infrared thermal imager in the coal mine rock burst, and coal and gas outburst sensing alarm based on thermal infrared image is proposed, and a method to monitor the moving speed of temperature abnormal objects under the condition of forward tilt angle of infrared thermal imager is proposed. According to the actual driving roadway of the Shuangma Coal Mine in Ningxia, combined with the frame rate of infrared thermal imager of 25 FPS, focal length of 13 mm, and the field angle of view along the axial direction of roadway of 21°, the optimal dip angle of infrared thermal imager obtained by this method is about 58° on the premise of ensuring the velocity measurement effect. During image monitoring, the monitoring range is increased by 292%, and the cost of infrared thermal imager in the intensive monitoring area is reduced by nearly 75%. In order to meet the disaster characteristics more realistically, simplify the complexity of the experiment and ensure the safety, a set of disaster temperature and velocity characteristics simulation experimental equipment is designed: a 315 mm PVC tube is used to simulate the circular roadway; the 10 mm rubber ball with similar color and specific gravity is used to replace the crushed coal rock as the main experimental material and the main identification target. Physical heating method (hot water bath) is used to make the temperature of rubber ball reach the abnormal range of temperature when the disaster occurs. The high pressure blower is used to provide power source, so that the speed of the rubber ball can reach the abnormal range of speed when the disaster occurs. The infrared thermal imager is used to monitor the whole simulated disaster process and capture the thermal infrared video image. The proposed disaster perception alarm method is coded. The results show that the recognition effect of this method is good, and the feasibility and effectiveness of the detection and alarm method of coal burst, and coal and gas outburst based on thermal infrared image are verified.