沉管隧道接头剪力键抗震性能及减震措施

为提高沉管隧道接头的抗震安全性，设计了一种减震装置，完成了有无减震装置2组1/4大比例尺的接头剪力键模型往复加载拟静力对比试验. 通过试验揭示了沉管隧道接头剪力键模型在水平循环荷载下的力学行为及抗震性能，并验证了新型减震装置在沉管隧道接头减震中的可行性. 试验结果表明:无减震模型在循环剪切荷载下，凹槽端部率先出现裂缝，随后剪力键端部开始出现裂缝，随着加载位移的增大，剪力键出现较大塑性变形后失效；减震模型在循环剪切荷载下减震装置先出现局部屈曲，随后剪力键出现剪切破坏，减震装置可延迟剪力键的开裂时间；与无减震模型相比，减震模型在输入相同的加载位移时，其开裂荷载、屈服荷载、峰值荷载及破坏荷载分别提高了45.2%、37.33%、26.8%和29.2%；减震装置对模型初始刚度影响相对较小，且能满足规范限定的接头容许位移；单圈滞回耗能最大可提高55.1%，累积滞回耗能提高了31.9%，该减震装置可较好地提高剪力键的整体抗震性能. 

Seismic Performance and Damping Measures of Shear Keys for Immersed Tunnel Joints

In order to improve the seismic safety of immersion joints, a new type of damping device for immersed tube tunnel joints was designed, and two groups of quasi-static tests were performed using a 1/4 scale shear key model with and without the damping device for comparative analysis. Through the tests, the mechanical behavior and seismic performance of the immersion joints under horizontal cyclic loading were revealed, and the feasibility of applying the new damping device in the vibration reduction of the immersed tunnel joint was verified. The results show that under the cyclic shear load, cracks first appear at the groove end of the traditional joint model, and then appear at the end of the shear key. As the loading displacement increases, the shear key experiences a large plastic deformation and then fails. Under the cyclic shear load, the damping device first suffers a local buckling, and the shear key is then subject to a shear failure. The damping device can delay the cracking time of the shear key. Compared with the traditional model without damping equipment, the cracking load, yield load, peak load and failure load of the damping model are increased by about 45.2%, 37.33%, 26.8% and 29.2%, respectively, under the same loading displacement. Meanwhile, the influence of the damping device on the initial stiffness of the model is relatively small, and it can meet the allowable displacement of the joint specified by the relevant code. The single-loop hysteretic energy consumption and the cumulative hysteretic energy consumption can be increased by 55.1% and 31.9%, respectively. Overall, the damping device can effectively improve the seismic performance of the shear key.