Roof Water In Deep Coal Seam Detected By Ground Transient Electromagnetic Method In Buertai Mine,Shendong

With the development of coal mining in China,the roof water damage is an important factor affecting the safety of mine production in the process of roadway excavation or face mining.In order to verify the reliability of surface transient electromagnetic method in detecting deep coal seam roof water,further improve the accuracy of transient electromagnetic data interpretation,and provide technical support for coal mine water prevention and control.In this paper,combined with numerical simulation,inversion algorithm optimization and field detection test,the experimental study of transient electromagnetic detection on the roof water surface of deep mining face in Shendong Buertai Mine was carried out,and the following understandings were obtained:(1)The electrical structure of strata in Buertai mine of Shendong shows the QHAKH characteristics of "high—slightly low—low—high—higher—low—high".In the study area are transient electromagnetic exploration launch of roof water use 600 X 600 m length of wire frame detection effect is best,setting parameters in the subsequent numerical simulation study has guiding significance.(2)The 3D numerical simulation results intuitively show the diffusion law of the transient field in half space from the perspective of "volume—plane—line—point".At the same time,it is clear that the difference of the transient field response between the non-center point and the center point of the large fixed source TEM is mainly shown in the early and middle stages.The early stage shows the characteristics of "high—low—high" H-shaped curve,and the middle stage shows the characteristics of "low—high—low" K-shaped curve,and the relative error of the induced electromotive force increases with the increase of the offset.(3)The response characteristics of the transient field under different water cut conditions are relatively different;For the same aquifer,the larger the water intensity,the larger the response amplitude and response time window of the transient field.For multiple aquifers,with the increase of the depth and number of aquifers,the response time window of the transient field moves back,and the longitudinal resolution of the aquifers decreases.(4)Compared with the traditional smoothing model,the resistivity 1D constraint model based on prior information is more consistent with the vertical variation characteristics of the actual strata,and has strong vertical resolution ability for the horizon,which can effectively constrains the multi-solution of the inversion results and improve the accuracy of the interpretation of transient electromagnetic data.(5)Combined with the field test results,the constrained inversion method is used to conduct electrical imaging on the measured data,and the delineated abnormal area is verified by drilling,and the detection results are reliable.Based on theoretical and practical research,this paper demonstrates the feasibility of large fixed source transient electromagnetic method in detecting the roof water of deep mining face,which provides a reference for Shendong Buertai Mine and other mines with similar stratum geological conditions.Figure[45]table[14]reference[105]...