Double-shield TBM Mounted Seismic Ahead-prospecting System and its Application

Abstract

Double-shield tunnel boring machine (TBM) has been widely used in tunnel construction. However, the unknown adverse geological conditions in front of the tunnel face can easily disturb the construction progress of the double-shield TBM. To ensure the construction safety of double-shield TBM, it is necessary to predict the geological information in front of the tunnel face in advance. However, the unique tunnel environment with a double-shield TBM makes it hard to predict geological conditions by conventional detection techniques. Therefore, this paper proposes a double-shield TBM-mounted seismic ahead-prospecting system. According to the special structure of double-shield TBM, a geological detection system mainly including the vibration source and rod-sensing elements was developed. The mounted vibration source is excited by high-pressure gas, and the excited seismic signal has strong energy, which can realize long-distance disaster prospection. The rod-sensing element can directly contact the surrounding rock mass through the grouting hole and collect reflected wave signals with a higher signal-to-noise ratio. The system can directly excite and receive seismic waves in the rock mass around the tunnel. The proposed system has been mounted on double-shield TBMs and verified based on field.