Exploration of Tunnel Alignment Using Integrated Geophysical Methods: A Case Study in China-Burma Gas Pipeline Tunnel

Abstract

The technique of engineering geophysical methods, which can predict the geological conditions in advance to improve construction progress, are widely adopted during tunnel excavation. While every geophysical method has the defect that the geophysical anomaly has interpretation ambiguity, it’s the key to reduce the ambiguity and uncertainty of geophysical anomalies in the tunnel exploration. Aims to improving the accuracy of prediction of hazardous, the integrated geophysical methods are proposed to detect and check geophysical anomalies mutually and then deduce weathered zone, faults and Karst caves. In this paper, basic theories, applicability and field working methods of combined shallow seismic refraction and CSAMT, multi-electrode resistivity imaging as well as ultrasonic logging are introduced and the methodology of integrated geophysical methods are proposed by using a case study on a part of tunnel alignment of China-Burma gas pipeline. The interpretation results deal with the geophysical anomalies to demarcate weathered zone, yield corresponding elastic parameters of rock, and figured out faults and Karst caves that surrounded the cave line. The results showed that the integrated geophysical methods should be promoted in tunnel exploration.