不同拼装方式下盾构隧道管片衬砌受力与破坏模式模型试验研究

管片拼装方式通常包括通缝拼装和错缝拼装两种形式，在不同工程中均有应用，拼装方式的不同直接造成管片衬砌结构体系上的差异，导致相同荷载条件下结构受力及破坏形态的显著差异。以狮子洋隧道为工程背景，采用相似模型试验方法，对比分析不同拼装方式对管片衬砌结构的力学特性及破坏特征的影响规律。试验结果表明：拼装方式对管片衬砌结构的力学性能及破坏形式影响显著，通缝拼装方式整体刚度相对于错缝拼装方式较小，衬砌结构发生失稳时，通缝拼装方式极限承载力最低，其临界失稳位移最大，在管片衬砌结构开始发生宏观破坏后迅速进入失稳阶段，承载力丧失具有突发性，衬砌结构破坏最为严重|错缝拼装提高了管片衬砌结构的极限承载能力，结构从局部出现宏观裂纹到发生整体失稳的过程较长，具有明显的渐进性特征，其中错缝拼装方式CF2的失稳开始荷载最大，临界失稳位移值最小，失稳破坏过程的渐进性明显，有利于管片衬砌结构承载及防水的需求。

A model test for the mechanical property and failure mode of lining segments with different assembly types of shield tunnel

The assembly types of lining segments are generally categorized into the straight joint assembly and the staggered joint assembly. The differences in lining structure caused by assembly type may lead to distinct discrepancies in the mechanical behaviors and failure modes of structure under the same loading conditions. With Shiziyang shield tunnel project taken as an example and based on the similarity model test method, the comparative analysis on mechanical properties and failure modes of lining segments with different assembly types was conducted. The results show that the assembly type has significant influences on the mechanical properties and failure modes of lining structure. The rigidity of lining structure with straight joint assembly is smaller than that with staggered joint assembly. The lining structure with straight joint assembly has the lower ultimate bearing capacity and larger critical displacement when the critical failure state of structure is approached. Meanwhile, once the macroscopic failure of lining structure occurs, it quickly goes into the unstable phase, characterized by the sudden loss of bearing capacity of the structure and the most serious damage and failure of lining structure. The ultimate bearing capacity of lining structure can be increased by the staggered joint assembly. The entire process from local macro-crack to the overall failure of structure is relatively long and characterized by the remarkable progressive. Particularly, with the staggered joint assembly type, the bearing capacity of CF2 is largest before its failure and its displacement at critical failure state is smallest.