水下盾构对接拆机后管片应力松弛控制措施研究

盾构对接技术凭借其“相向掘进、地中对接、洞内解体”等技术特点，在水下盾构隧道施工中的应用愈加频繁，由于技术尚不完善，盾构拆机导致的掌子面失稳和管片衬砌应力松弛等问题亟待解决。依托某海底隧道工程，针对盾构地中对接管片槽钢加固技术展开研究，建立了管片衬砌壳 连接器模型，通过在环间预留间隙实现了管片环缝的模拟，计算了管片环之间的连接强度，能够详细模拟不同荷载下的环缝张开量。以环缝张开量为判断标准，对比分析了加固范围、槽钢数量和槽钢型号等因素对加固效果的影响，研究结果表明：随着加固环数的增多，最大轴向位移和环缝张开量均呈现先减下后增加的趋势；随着槽钢的数量增多、型号变大，最大轴向位移和环缝张开量逐渐减小，减小趋势逐渐放缓，离盾尾较远的管片环加固效果相对较弱。

The control measures of stress relaxation of segment after #br#underwater shield junction and dismantling

The technology of shield junction is more and more frequently used in the construction of underwater shield tunnel. As the technology is not perfect, the instability of the tunnel face and the stress relaxation of segment lining caused by shield machine dismantling need to be solved. Based on a subsea tunnel project, the technology of reinforcing segment with channel steel in the process of shield junction is studied. The shell-connector model of segment lining is established. By reserving the gap between the rings, the simulation of the ring gap between the segments is realized. The connection strength between the segments and the rings is calculated, which can simulate the width of the circular gap under different loads in detail. The influence of reinforcement range, channel steel quantity and channel steel type on reinforcement effect is analyzed. The results show that: With the increase of the number of strengthening rings, the maximum axial displacement and the width of the ring joint decrease first and then increase; With the increase of the number and type of channel steel, the maximum axial displacement and the width of ring joint gradually decrease, and the decreasing trend gradually slows down.