Time-lapse change pattern and mechanism of resistivity of coal seam floor mining damage based on inter-hole DC perspective
During the coal mining process,the change in the floor stress state of coal seam will produce deformation and failure.The seam floor failure in different coal mining processes has a certain law.At present,the water disaster monitor-ing of coal seam floors based on the DC resistivity method mainly focuses on the resistivity response characteristics of floor deformation and damage.To investigate the temporal changes in the electrical properties of the coal seam floor dur-ing mining,this study employs the inter-hole DC perspective observation system and the time-lapse resistivity reflection coefficient method.Through numerical simulation and field tests,the study uncovers the temporal variation law of the res-istivity of coal seam floor induced by mining activities.First,this paper compares the results of individual inversion and time-lapse resistivity change rates for a typical geoelectric model to validate the reliability of the inter-hole DC perspect-ive time-lapse method.Next,considering the mining-induced damage to the coal seam floor,this paper analyzes the elec-trical response patterns and charac-teristics of the rise of confined water and the damage zone in the floor during the min-ing process.It also discusses the feasibility of using a time-lapse resistivity reflection coefficient to assess the depth of coal seam floor damage,offering a theoretical basis for field construction.Finally,,the on-site monitoring tests reveal the elec-trical change characteristics of coal seam floor during the coal mining process.The time-lapse resistivity reflection coeffi-cient R is utilized to determine the damage depth of the rock layer of the working face floor,which is found to be 15 m.The study results demonstrate that the time-lapse characteristics of the resistivity of coal seam floor mining damage ob-tained by the inter-hole DC perspective method can mitigate the influence of formation factors and random noise in the monitoring data to a certain extent.Additionally,the time-lapse resistivity reflection coefficient can be utilized to determ-ine the depth of coal seam floor failure.This method transforms the detection target from the single study of geological an-omalies to the full life cycle dynamic monitoring of the floor damage of the working face in the process of coal mining and then realizes the detailed depiction of structural damage to the working surface floor.
time-lapse monitoringmining damageinter-hole direct current perspectiveforward simulationcoal seam floor
万方数据
维普
