舟山灌门水道隧道最小岩石覆盖厚度研究

Study on Mininum Rock Cover for Zhoushan Guanmen Strait Tunnel

总结了确定海底隧道最小岩石覆盖厚度常用的方法,并分析了各种方法的适用条件。基于大量弹塑性海底隧道稳定性数值分析,提出了最小岩石覆盖厚度的最小位移法判据。根据舟山灌门水道隧道地质勘察报告,选择海底深槽和钻孔位置5个控制性分析断面。分别依据上述各种方法确定了舟山灌门水道隧道拱顶曲线,最后给出了各个分析断面的最小岩石覆盖厚度建议值。

Minimum rock cover thickness is an important parameter in vertical alignment design of subsea tunnells, and affects subsea tunnel cost and security. General methods are summarized for determining the minimum rock cover thickness in subsea tunnel, including engineering analogy method and numerical analysis method. Additionally, appropriate conditions are analyzed for all methods. Minimum distance method is presented for minimum rock cover thickness based on a great number of numerical analysis experiences. According to the Zhoushan Guanmen Strait Tunnel geological investigation report, 5 key cross-sections are selected. Minimum rock covers for 5 key cross-sections are obtained based on three types of analogy methods and numerical methods. Finally, the design value of minimum rock cover is provided through integrative analysis according to the topographical and geological condition of Zhoushan Guanmen Strait Tunnel.