(1. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China；2. Institute of 3S and Subsidence Engineering，China University of Mining and Technology，Beijing 100083，China)
Abstract：Based on existing technology，a new survey method is proposed for the tunnel photography measuring system. To get the coordinates，the system uses cameras，coder and compass. First，the fundamental principles are introduced based on the system；and the operation process，parameter setting and structural design of this device are analyzed. Then，according to the data characters，the methods to remove the false elements and to revise the imprecise elements are given. Finally，through ray analyses，it presents the mathematical model for digital tunnel¢s creation；and the results of case study are analyzed. According to the problems of the system，it presents the target of further research and the key issues that should be solved.
