等值反磁通瞬变电磁在隧道超前地质预报中的解释方法研究与应用

Research on interpretation method and application of opposing coils transient electromagnetics on advanced geological forecast

瞬变电磁法具有对低阻体反应灵敏的特点,在探测隧道掌子面前方含水或充泥断层、破碎带等低阻不良地质体上具有独特的优势。这里首先简单介绍了等值反磁通瞬变电磁法的原理及特点,然后通过对隧道全空间域高低阻模型一维正演曲线响应特征、视电阻率及视纵向电导曲线的解释特点和效果进行较为全面地分析研究,提出并分析了视电阻率等值线图与视纵向电导断面图联合解释方法。最后通过两个应用案例,总结出等值反磁通瞬变电磁在隧道超前地质预报成果解释中的一些特点和规律。结论表明,等值反磁通瞬变电磁方法适用于隧道超前质预报工作,能够有效提高预报成果的精度及准确度。

Transient electromagnetic method is sensitive to low-resistance bodies and has unique advantages in detecting water-bearing or mud-filled faults,broken zones,and other low-resistance unfavorable geological bodies in front of the tunnel face.First,this study introduces the equivalence principle and characteristics of the Opposing Coils Transient Electromagnetics method.Then through the tunnel,the high and low resistance in the spatial domain sandwich model one dimensional forward response characteristics,the apparent resistivity curve,and the interpretation of the apparent longitudinal conductance curve characteristics and effect of comprehensive analysis and research,discusses the combined interpretation method of apparent resistivity contour map and apparent longitudinal conductivity section is discussed.Finally,two application cases summarize some characteristics and rules of Opposing Coils Transient Electromagnetic method in interpretation of tunnel advanced geological prediction results.The conclusion shows that the Opposing Coils Transient Electromagnetic method is suitable for tunnel advanced quality prediction and can effectively improve the accuracy and accuracy of prediction results.