| In the process of building long tunnels in my country,in order to avoid engineering geological problems such as bad water disasters,advanced geological forecasting of tunnels is introduced for detection.Based on the background of several example projects of Baiyunshan Tunnel and Wanggangshan Tunnel,this paper first systematically expounds the principle of transient electromagnetic method and YCS2000 transient electromagnetic instrument.It is generally believed that transient electromagnetic method is usually sensitive to water-bearing structures,but Because the Baiyunshan Tunnel is a gas tunnel,it passes through multiple reservoirs,and the geological conditions are complex.Only a single transient electromagnetic method may not fully predict the surrounding rock conditions in front of the forecast section.Therefore,combined with the TSP（Tunnel Seismic Prediction ahead）system and geological conditions A total of three comprehensive geophysical means of radar method are used for comprehensive forecasting.Secondly,the data processing software of YCS2000 mine transient electromagnetic instrument,which is widely used in China at present,can only make frequent-apparent resistivity section mapping due to the lack of inversion calculation,and the mapping and prediction results have certain deviation from the real situation.In this paper,the regularization inversion strategy is used for inversion processing,and the improved data processing program is verified in the Tunnel section of Wanggang Mountain,and the comparison shows that the improved results can more accurately predict the location of water.The main results are as follows:1.Analyze the necessity of comprehensive advanced geological forecast technology for key sections of tunnels.The original treatment system of YCS2000 TRANSIENT electromagnetic method has advantages in the water exploration position,but there is a deviation of ±20m,so it is improved.The TSP method is sensitive to the fracture zone and can predict the location of water,but the water content and accuracy are biased.The prediction distance of GPR is short and the expression of broken zone is not clear.Therefore,the improved software is used to deal with and demonstrate the comprehensive forecast.2.For the data processing software of YCS2000 mine transient electromagnetic instrument,there is no inversion calculation.In addition to inheriting the original processing module such as data smoothing and filtering,the improved software also adopts regularization theory to conduct inversion research on the data,forming a software system.Compared with the original treatment software,it can determine the location of water more accurately.The transient electromagnetic data of PK157 +600 section of Wanggangshan tunnel of Yumo Railway is collected and processed by using the improved software.The results show that the software can accurately determine the position of water containing water,and its error is reduced from ±20m to ±5m.3.The improved YCS2000 processing system transient electromagnetic instrument,the TSP system,geological radar of baiyun mountain tunnel DK132 + 472 ～ + 442 section of comprehensive prediction,the results show that the comprehensive prediction technology can not only avoid the shortcoming of a single method can greatly improve the accuracy of the forecast results. |
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