The Geological Exploration Applied Reseaearch Of Shield Mining Based On The Transient Electromagnetic Method

This paper use the transient electromagnetic method to do the geological exploration forecast, focused on optimization problems of geological exploration in tunnel engineering. In the excavation of the subway tunnel, the shield machine is used as the major mining tool, it is necessary to accurately forecast the advance. The transient electromagnetic method has been put into use in the engineering exploration forecast of half-space ground, and achieve better results,but has no applications in the underground space. The transient electromagnetic method is an exploration method underground space geological conditions to do forecast based on the theory that different ohmic losses caused the different degree of change of the magnetic flux density.This topic is based on the transient electromagnetic method, to do observation and research on the medium magnetic induction decay curve under the conditions of the whole space.This paper studies the transient electromagnetic method as the basis of the theoretical research, with MATLAB data processing, using finite element analysis software ANSYS to simulate the propagation characteristics of homogeneous half space and full space transient electromagnetic field, to do the two-dimensional transient electromagnetic field computation. In the conditions of half space, compare and analysis the response curves made by the abnormal body with good conductivity of transient electromagnetic and simulation, to verify the correctness and feasibility of the model. Through the ANSYS simulation the underground magnetic induction response status of the full space and half-space, we get the different responses, under the two space, the full spatial response value is bigger. Specific we do the analysis of response to the situation of different parameters of abnormal body under the whole space, and study the sensitivity of the different parameters of abnormal body of transient electromagnetic exploration. We change the conductive properties of surrounding rock to study the sensitivity of the surrounding rock resistivity reaction of the transient electromagnetic method. It is more convenient to display simulation picture by using VB editor interface. We use the Wavelet processing to do the data processing, get better experimental curves, and then compare the experimental curves under different circumstances.We do analysis of the results of the simulation under different circumstances, and get the conclusion that:transient electromagnetic method is sensitive to the detection of a low resistivity anomaly body, has better response to the size and depth, but is not sensitive to the probe of the surrounding rock.The experimental results match with the simulation results after wavelet processing to the experimental data.