盾构隧道管片接缝密封垫防水性能及受施工荷载影响研究

为研究盾构隧道接缝密封垫防水性能及施工荷载对其影响,依托某地铁盾构隧道工程自主研制密封垫防水性能足尺试验装置,设计并开展相应的足尺试验。在此基础上,建立密封垫数值分析模型并结合试验结果验证了其可靠性。借助数值分析得到了不同错台量条件下的密封垫防水性能变化规律。最终,构建了盾构隧道三维荷载-结构模型,综合考虑注浆压力、千斤顶推力和盾尾刷反力等施工荷载,探究了接缝变形特征及其对密封垫防水性能的影响情况。研究结果表明:极限状态下工程原设计密封垫无法满足设计水压要求;接缝错台量增大将导致密封垫偏心受压越发严重,可能引起欠压侧支腿翘起;相同施工荷载下,最大环缝变形为最大纵缝变形的1.5~2.0倍,环缝密封垫防水性能降低程度更大;确定密封垫极限状态时有必要考虑施工荷载造成的接缝变形。所提出的足尺试验装置能够很好地实现试验目的,相应方法与结果可为后续盾构隧道接缝密封垫防水性能足尺试验研究提供参考和指导。

Waterproof Performance of Sealing Gaskets and Impact of Construction Loads on Segment Joints in Shield Tunnel

To study the waterproof performance of sealing gaskets and the impact of construction loads on shield tunnels, a full-scale test device based on a metro shield tunnel project was independently developed and the corresponding full-scale tests were designed and performed. Subsequently, for the sealing gaskets, a numerical model was established and its reliability was verified through comparison with the test results. Further, through numerical analyses, the changing rule of the waterproof performance of the sealing gaskets was obtained under different offset conditions. Moreover, a three-dimensional load-structure model was established for the shield tunnel linings. The joint deformation characteristics and their influence on the waterproof performance of the sealing gaskets were explored by considering construction loads such as the grouting pressure, jack thrust, and shield tail brush reaction force. The results show that the originally designed sealing gaskets do not meet the design water pressure requirements under the limit state. An increase in joint offset intensifies the eccentric compression of the sealing gaskets, which may cause the legs to be lifted under insufficient compression. For a fixed construction load, the maximum deformation of the circumferential joint is approximately 1.5 to 2 times that of the longitudinal joint; additionally, the waterproof performance of the sealing gaskets for the circumferential joint is reduced significantly. Therefore, it is necessary to consider the joint deformation caused by construction loads when determining the limit state of sealing gaskets. This can be achieved using the full-scale test device proposed in this paper. Moreover, the corresponding methods and results can be used as a reference for subsequent full-scale test research on the waterproof performance of sealing gaskets utilized in shield tunnels.