双护盾TBM隧道施工期管片开裂分析

针对多雄拉隧道在双护盾TBM施工中的管片破损现象，开展了管片开裂时机、裂缝大小及分布、管片错台量统计分析； 并在此基础上通过数值计算，对管片结构在正常掘进、脱困状态、油缸偏移、拼装错台工况下是否开裂进行了分析。研究表明： 1）现场管片破损以开裂、错台为主，大部分初始开裂发生在尾盾外10 m范围内； 2）管片以纵向开裂为主，且集中在边墙以上部位； 3）在TBM正常掘进、脱困掘进状态下，管片不发生开裂，管片结构设计满足要求； 4）在单因素影响方面，辅助油缸偏移和管片错台对管片结构受力影响较大，当油缸作用点偏移管片中心线外大于3 cm和管片纵向错台超过7 cm时，容易引起管片开裂，施工中应予以重视。

Segment Cracking Analysis of Double Shield TBM Tunnel in Construction Stage

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.