Development of a Compact Survey System for Small Shield Tunneling

A compact survey system for small shield tunneling has been developed. The real time data acquisition system offers information on pitching, tolling and yawing of the shield machine as well as location. A set of the system comprises a target including three LEDs and a prism reflector, a detector including a TV camera and an electronic transit, and a image processor. Since the detector is placed far from the shield machine, the system can be applied to small tunneling under 4meter of diameter, whereas existing survey systems in laser technology can be applied only to large shield tunneling due to their target size. The performance of the system has been proven through on-site uses at small shield tunneling projects.