Abstract: The erection precision and appearance quality of the segments, as well as the transportation efficiency in the tunnel, are reduced due to the rotation of tunnel segments caused by the overtorque of the cutter head and the improper posture of the shield TBM. The causes for the segment rotation are analyzed, with the tunneling of a singleshield TBM in soft ground as an example. Countermeasures, including improving the structural design of the cutter head, optimizing the boring parameters, proper selection of cutting tools, timely cleaning the cutter head and sacrificing the circumferential and longitudinal joints of the segments, are taken, which solves the segment rotation problem successfully.

Key words: singleshield TBM, cutter head, torque, segment, rotation