湛江湾高水头跨海盾构隧道管片结构典型断面受力计算与监测反馈分析

Force determination and monitoring feedback analysis of typical sections of lining structure of cross-sea shield tunnel under high head in Zhanjiang bay

湛江湾隧道是目前国内最深的跨海盾构隧道,其管片采用斜螺栓连接,错缝拼装,分别采用修正惯用法及梁-弹簧法计算最大覆土断面与最大水深断面管片的受力,并将实测管片受力、水-土压力值与理论计算结果进行比较,分析水-土压力分布模式,结果表明,修正惯用法与梁-弹簧法均可以较好地模拟隧道管片的受力形态,而梁-弹簧法比修正惯用法更接近实测结果;管片呈压扁状态,梁-弹簧法结果受封顶块的位置影响较大;太沙基松弛土压力及水-土压力线性分布模式对深埋海底隧道是适用和安全的;对于本工程来说,管片外荷载以径向水压力为主,是影响管片轴力的主要因素。以上成果可为今后跨海高水头盾构隧道管片的设计及施工提供参考。

Currently, Zhanjiang bay tunnel is the deepest cross-sea shield tunnel in China. The tunnel segments are connected by oblique bolts with staggered arrangements. In this study, the forces in the maximum covering soil section and the maximum water depth section were calculated by a modified usage method and a beam-spring method, respectively. Then the distribution pattern of water-earth pressure was analyzed by comparing theoretical results with measured results of segment stress and water-earth pressure. The analytical results show that both of the modified usage method and the beam-spring method can well simulate the stress state of tunnel segment. Especially, the results calculated by beam-spring method is relatively closer to measured results than those by the modified usage method. It is found that segments are in flattening states and the results obtained by beam-spring method are greatly affected by the position of capping blocks. Terzaghi＇s relaxed earth pressure and the linear distribution of water-earth pressure are also applicable and safe for the deeply buried submarine tunnel. In this project, the lateral load of the segment is dominated by radial water pressure, which mainly affected the axial force. Therefore, this study can provide a useful reference for the design and construction of high-head cross-sea shield tunnel segments in the future.