双侧卸载工况下盾构隧道错缝拼装结构变形特征

Deformation Characteristics of Shield Tunnel with Staggered Joints Under Bilateral Unloading Condition

摘要:

依托厦门地铁2号线区间隧道，采用相似模型试验和有限元数值模拟分析了隧道双侧卸载工况下结构的受力变形特征、破坏形式及损伤过程，得到盾构隧道管片错缝拼装结构在双侧卸载工况下的变形控制指标.结果表明，管片混凝土裂缝宽度达到设计允许值0.15 mm时的收敛变形值为3.29‰D（D为隧道直径）；螺栓屈服时收敛变形值为10.67‰D，结构破坏形式表现为由管片开裂、螺栓屈服直到变形过大并垮塌.

Abstract:

Based on the engineering background of the Xiamen Metro Line 2 tunnel, the similar model test and the finite element numerical simulation were used. Aiming at the shield tunnel’s unloading conditions on both sides, the transverse deformation characteristics, failure modes and segment damage process of tunnel were analyzed, and the stress mechanism and the key performance points of shield tunnel under unloading condition were obtained. The results show that: the convergent deformation value of segment concrete crack width 0.15 mm of design allowable value is 3.29‰D (D is the diameter of the tunnel); the vertical section of bolt failing to yield is 10.67‰D, the structural failure form is caused by segment cracking, bolt yielding to excessive deformation and collapse.