Hydraulic tomography identification of concealed water-conducting channels in coal mine floor

LIU Juan

doi:10.13347/j.cnki.mkaq.20250722

Abstract：The identification of concealed water-conducting channels in coal seam floor and the simulation and evaluation of seep-age field are the key to the prevention and control of mine water inrush.Geophysics exploration techniques can identify the spatial structure distribution of concealed water-conducting channels,and the inversion results need to be converted into hydrogeological parameters before they can be used for seepage field simulation of floor aquifers,however,the simulated values of water pressure are not in good agreement with the measured values.In hydraulic tomography,the spatial non-uniform distribution of hydrogeological parameters in the aquifer is directly inverted by the water pressure monitoring value to identify the water-conducting channel,which ensures the accuracy of seepage field simulation.Therefore,the sand box test was used to study the characteristics of water pressure fluctuation in karst aquifer with water passage based on borehole slug test,and the hydraulic tomography inversion identification of water passage and the prediction and comparison of seepage field were carried out according to the monitoring data,finally,numeric-al experiments are used to study the influence of the number of monitoring holes,the number of excitation sources,and the prior geo-logical information of geophysical prospecting on the identification accuracy.The results show that the water pressure fluctuation curve inside the water-conducting channel presents the characteristic of a rapid increase followed by oscillatory attenuation,while the water pressure fluctuation curve outside the water conducting channel presents the unimodal distribution form of rise and then slow decline.The closer the distance to the source is,the larger the peak value of water pressure fluctuation is.The farther the distance is,the smaller the peak value of water pressure fluctuation is and the time of water pressure fluctuation is delayed.Compared with the inversion results of hydraulic conductivity which can roughly describe the structural characteristics of water channel,the spatial res-olution of the inversion results of water storage coefficient is lower;compared with increasing the number of monitoring holes,the spatial resolution of the inversion results of water storage coefficient is lower,increasing the number of excitation sources can signi-ficantly improve the identification accuracy of water channel.If the geophysical results are quite different from the structure of the real water channel,the wrong geophysical results can be used as prior geological information,and it will significantly reduce the ac-curacy of hydraulic tomography identification.