Detection of water-rich fractured rock masses along proposed railway tunnel routes using three-dimensional aero-electromagnetic methods

Abstract

Abstract Water inrush (gushing) is one of the primary hazards affecting the construction of underground engineering works, such as tunnels. The detection of water-rich fractured rock masses in the proposed routes of long trans-mountain tunnels is a significant engineering challenge. The traditional ground-based geophysical exploration methods are limited by rugged terrain. On the other hand, the aero-electromagnetic technique relies on differences in the resistivity of water-bearing and dry rocks to locate underground water. Using multi-dimensional geophysical data, this technique can improve the accuracy of exploration, locating masses of water-rich fractured rock along proposed routes of trans-mountain tunnels and guiding route selection. While promising, this technique is relatively young; thus, more research on their efficacy is required. In this study, aero-electromagnetic surveys of the Zheduoshan Tunnel of the Sichuan–Tibet Railway were conducted, and the feasibility and validity of the method were verified by directly collecting data from deep boreholes. The aero-electromagnetic technique is shown to have good application potential for improving the efficiency of geophysical exploration.