Research on 3D monitoring and intelligent early warning system for water hazard of coal seam floor

Aiming at the problems of incomplete coverage of monitoring points and low intelligent level of karst water disaster of coal mining in Northern China-Type coalfields,on the basis of the theory of “Down Three Zones”,a comprehensive monitoring and early-warning technical method was proposed,which is composed of the multi-frequency continuous electricity method monitoring source of water-inflow, and “ tunnel-ground-borehole” joint micro-seismic technology monitoring of water filling channel during mining,and the intelligent early warning technology of water dis- aster based on monitoring data. Among them,the multi frequency continuous electrical method monitoring system takes the pseudo-random multi-frequency series as the artificial field source,uses the multi-frequency series and other detec- tion technologies to extract the weak signal in the strong noise background,and uses the quasi Gauss-Newton method to carry on the full space three-dimensional resistivity inversion to the pre-processing data,so as to realize the automation and three-dimensional monitoring of change process of the water inflow. The “roadway-ground-borehole” joint micro- seismic monitoring system is mainly based on the three-dimensional deployment of sensors and recovery devices in the borehole,the underground wired (IEEE1588) and ground wireless (GPS) time synchronization method is used to re- alize the synchronization of ground and underground data collection time,then the real-time transmission network of monitoring data is established,and the three-component positioning calculation based on polarization analysis joint in- version is carried out. The method realizes the accurate location of the fracture position of the water conducted chan- nel,solves the problems of the precise location and the real-time monitoring of the water inrush channel. The intelligent early warning system uses the time series big data mining technology and the computer deep learning technology to an- alyze and process the massive monitoring data from electricity and micro-seismic,and uses the index early warning and the model early warning method to predict the spatial distribution of the monitoring data and the real-time danger lev- el. Finally,the paper took the 11916 coal face of the Gequan coal mine as the application site,and adopted multi-fre- quency continuous electrical monitoring system,“ roadway-ground-borehole” combined micro-seismic monitoring sys- tem and intelligent early warning system to carry out three-dimensional monitoring and intelligent early warning for the karst water damage in the coal seam floor. The study results provides a technical and equipment support for the monito- ring and early warning of coal seam floor water hazard.