Abstract: In order to fit any spatial design curve in the layout of segments for rectangular shield tunnel, a layout technology of semiuniversal ring segments for rectangular shield tunnel is proposed. This technology needs only four positions based on two types of segments to complete the fitting of plan and vertical curves simultaneously. Using Visual Lisp, the composition program of semiuniversal ring segments for rectangular shield tunnel is developed. The technology is applied to the segment prelayout of project with a 500 m radius curve to verify its feasibility. The results show that: (1) The quantity of the two types of segments is almost the same. (2) The maximum deviation between fitted and theoretical horizontal curves is 16.6 mm, and the maximum deviation of  the vertical curve is 13.2 mm, which is within the allowace range of standard.

Key words:  rectangular shield, semiuniversal ring, curve fitting, segment assembly