Development and application of precursory information sensing technology in coal mine dynamic disaster

In order to solve the problems of the lack of sensing and monitoring technology for the precursory information of coal mine dynamic disasters, the low precision and poor stability of sensing equipment, this paper analyzed the development trend of coal mine dynamic disaster monitoring technology. It is proposed to use micro-seismic, stress, and gas concentration monitoring technologies as breakthrough points, to develop fiber optic micro-seismic, triaxial stress, distributed multi-point laser methane sensing technologies. A fiber grating three component acceleration sensor based on the fiber grating sensing principle, a microseismic monitoring device and system are developed. The microseismic frequency range reaches 0.5-300 Hz, and the average positioning error is about 11 m.The triaxial stress sensor and monitoring device based on wavelength division multiplexing (WDM) technology are developed, and the three-dimensional space stress vector measurement is realized. The measurement range is 0-30 MPa, and the measurement error is 3%.Based on the principle of laser absorption spectrum, a distributed multi-point laser methane monitoring device and system with multi optical path synchronous data acquisition is developed by using optical fiber optical path multiplexing technology and reference chamber self-calibration technology. The measurement range is (0-100)% CH4, the measurement error is ±3%, and the calibration cycle is 120 days. Finally, starting from the essence of dynamic disaster induced by mining stress disturbance, a technical framework for integrated monitoring of precursor information of coal mine dynamic disaster is constructed, which integrates the three systems of microseismic monitoring, dynamic stress monitoring and coal mine environmental monitoring. The microseismic monitoring system, as a regional monitoring means, monitors the location, energy and other macro data of microseismic sources in real time; As a means of on-site monitoring, the dynamic stress monitoring system is used to identify the impact danger area and degree in real time for the purpose of danger early warning; Combined with the gas emission dynamic index data monitored by the coal mine environmental monitoring system, the coal and gas outburst phenomenon is accurately monitored and forewarned. The system has been intensively demonstrated in Xinjing Mine, Shanxi Province.