水压对盾构管片衬砌力学特征与破坏形态的影响模型试验研究

水压力作为一个重要因素，对盾构隧道管片衬砌结构的受力状态及长期安全性具有显著的影响。文中依托广深港客运专线狮子洋盾构隧道工程，采用模型试验的方法，比较分析了0m、30m、60m三种不同水压条件下管片衬砌结构的内力、变形、声发射数据及裂纹产生发展等试验数据信息，探讨水压对盾构隧道管片衬砌结构受力状态及破坏特征的影响规律。研究结果表明：在一定范围内，水压的增加，延长了管片衬砌结构的弹性受力阶段及塑性发展平台，延缓了结构内部出现损伤破坏的时间，提高了衬砌结构的极限载能力。随着水压的增加，管片临界失稳点的最大位移与隧道外半径之比由2.33%增大到2.77%，但是由局部损伤破坏出现到管片衬砌结构整体失稳的过程变得更短，发展速度变得更快，管片的主要破坏形式由以受拉破坏为主变为以压剪破坏为主。

Research on the mechanical property and failure mode of shield tunnels with different hydraulic pressure by model test

The hydraulic pressure has a significant influence on the stress state of shield tunnel segment lining structure and long-term safety. Based on Shiziyang shield tunnel project, using the model test method, a comparative analysis of internal force, deformation, acoustic emission data and crack development test data of segment lining structures under three different hydraulic conditions was made. The influence of hydraulic pressure on the mechanical behaviors and damage characteristics the lining structure of shield tunnel was discussed. The results show that the increase of hydraulic pressure in a certain range prolongs the elastic stress stage and the plastic development platform of the segment lining structure, delays the appearance of damage and failure and improves the ultimate load carrying capacity of the lining structure. With the increase of hydraulic pressure, the ratio of the maximum displacement of the critical buckling point to the outer radius of the tunnel increases from 2.33% to 2.77%, the process from the appearance of partial damage to the overall instability of segment lining structure becomes shorter and the pace of development becomes faster, the main failure mode of the segment changes from tension failure to compression shear failure.