瞬变电磁法在隧道超前预报中提高信噪比的方法

The Method of Improving Signal-to-noise Ratio in Tunnel Advanced Prediction by Transient Electromagnetic Methods

瞬变电磁法在我国矿产勘察、工程勘察等多个领域已被广泛地应用,但在铁路隧道超前预报领域应用还是最近几年的事。这一新型技术的引进丰富了超前预报,但实践经验相对不足,提高瞬变电磁数据的质量是提高预报准确率的前提。因此就时域瞬变电磁法在隧道预报中如何提高信噪比做了理论阐述和模拟实践对比,首先在理论部分说明了如何选择合适增益及积分时间的方法,然后通过模拟对比及实际应用验证这两种方法。模拟对比及实际应用结果显示,选择合适的增益及积分时间能显著提高数据质量,从而达到提高预报准确率的目的。验证结果表明,这两种提高信噪比的方法在隧道超前预报中是可行有效的。

Transient electromagnetic method(TEM)has been widely used in many fields such as mineral exploration and engineering investigation in China,but its application in advanced prediction of railway tunnels is still in recent years.The introduction of this new technology enriches the advanced prediction,but the practical experience is relatively insufficient.Therefore,improving the quality of transient electromagnetic data is the premise to improve the accuracy of prediction.This paper makes the explanation of the theories and comparative analysis of simulation practices about how to improve the signal-to-noise ratio of time-domain transient electromagnetic method in tunnel prediction.In the theoretical part,how to choose the appropriate gain and integration time is explained.Then,the two methods are verified by simulation comparison and practical application.The results of simulation and practical application show that choosing the appropriate gain and inte-gration time can significantly improve the data quality and thus improve the accuracy of prediction.The validation results show that these two methods are feasible and effective in tunnel advanced prediction.