Abstract: The circular degree of shield tails should be inspected before the shield machines start boring, so as to guarantee the safety of shield tunneling and to avoid slurry leakage. The 3D photogrammetry measuring system is presented in terms of facility, theory and method. The deviation between the designed circular degree of shield tail and actual circular degree is measured and analyzed. The conclusions drawn are as follows: 1)The circular degree of shield tail can be measured rapidly and exactly by means of 3D photogrammetry technology. 2)The successful application of 3D photogrammetry technology in the quality inspection of the shield tail can provide reference for the quality inspection of shield machines in the future. 

Key words: shield tail, 3D photogrammetry, circular degree, inspection, deviation