跨海隧道泥水盾构钢套筒始发风险控制技术研究

Key techniques for risk control of steel sleeve launching of slurry shield cross-sea tunnel

为了探究跨海隧道泥水平衡盾构钢套筒始发风险控制技术,依托青岛地铁8号线大洋站至青岛北站区间海域段工程,阐述了在高水压富水复合地层中始发端采用洞门素墙+套管咬合桩+“U”型素墙+后退式注浆加固方式的优越性以及采用钢套筒辅助工法的必要性。通过分析相关工程经验,认为钢套筒在盾构始发期间的稳定性、密闭性及盾构始发参数合理性是保证盾构安全始发的要点,其中关键风险在于反力架、钢套筒的变形与位移、钢套筒各部位渗漏水、铰接密封失效、穿越加固体过程中滞排堵仓等,分析了钢套筒变形的原因与易发生渗漏水的位置。通过对类似工程的研究与本工程经验的总结,阐述了上述风险的控制方法,其中重点分析了反力架、钢套筒的变形与位移以及钢套筒各部位渗漏水的控制措施,通过有限元分析确定了钢套筒的适用性。各项措施在青岛地铁8号线大洋站至青岛北站区间海域段泥水盾构始发过程中应用后取得了良好的成效,为类似工程提供了工程经验。

To explore the initation risk control techniques of the slurry balance shields with steel sleeve in the cross-sea tunnel, based on the project of cross-sea tunnel between Dayang station and Qingdao North station of Qingdao Metro Line 8, the advantages of the portal element wall+casing biting pile+‘U’ type plain concrete diaphragm wall+backward grouting reinforcement method at the shield-launching end of the high-pressure water-rich composite stratum and the necessity of the steel sleeve auxiliary construction method are expounded. Through the analysis of relevant engineering experience, it is concluded that the stability and tightness of steel sleeve during shield launching and the rationality of shield launching parameters are important to the safety of shield launching. Among them, the key risks are the deformation and displacement of counterforce frame and steel sleeve, the leakage of water in various parts of steel sleeve,the failure of hinged seal, and the stagnant discharge and blockage in slurry tank in the process of crossing the reinforced soil. The causes of deformation of steel sleeve and the location of leakage are analyzed. Based on the research on similar projects and the summary of the experience of this project, the corresponding control methods for the above risks are presented. The control measures of deformation and displacement of the counterforce frame and steel sleeve as well as the water leakage in various parts of the steel sleeve are emphatically analyzed, the applicability of the steel sleeve is determined by finite element analysis. The application of various measures in the launching process of slurry shield in the cross-sea tunnel of Dayang station to Qingdao North station of Qingdao Metro Line 8 has achieved good results, which provides engineering experience for similar projects..