Abstract: Aiming at the segment damage phenomenon in the double shield TBM construction of Duoxiongla tunnel, the characteristics of segment cracking opportunity, crack size and distribution, segment dislocation are analyzed. On this basis, whether the segment is cracked are analyzed under normal driving, out of difficulty, oil cylinder offset, segment dislocation conditions through numerical calculation. The results show that: (1)Segment damage is mainly caused by cracking and dislocation and most of the initial cracking occurred within 10 m behind the tail shield. (2)The segments are mainly cracked longitudinally and concentrated above the side wall. (3)Under the condition of TBM normal driving and out of difficulty driving, the segment does not crack, and the segment structure design meets the requirements. (4)In the aspect of single factor influence, the displacement of auxiliary oil cylinder and segment dislocation have a great influence on the stress of segment structure; When the displacement of oil cylinder action point exceeds 3 cm outside the segment center line and the segment longitudinal dislocation exceeds 7 cm, it is easy to cause segment cracking, which should be paid attention to in construction.

Key words: double shield TBM, segment, segment cracking, segment dislocation