数值方法确定海底隧道最小岩石覆盖厚度研究

Study on numerical method for the minimum rock covers of subsea tunnels

目前国内正在修建或拟修建多条海底隧道,其中最小岩石覆盖厚度直接制约着海底隧道的安全和造价。本文根据国内外有关文献资料,探讨了利用数值方法确定海底隧道最小岩石覆盖厚度的方法,应用断裂损伤有限元和国际通用数值分析软件,根据隧道在同一剖面处不同底板线位置,隧道上方同一个点的位移收敛情况,建立了确定海底隧道最小覆盖厚度的位移收敛法。通过对国内2条海底隧道开展的研究,其中一条已开始施工,总结出了数值方法确定最小岩石覆盖厚度的思路和过程。为定量确定海底隧道最小岩石覆盖厚度建立了数值分析基础,最后应用数值方法确定某海底隧道最小岩石覆盖厚度。

At present, many subsea tunnels are being constructed and planned. The safety and cost of subsea tunnels are directly restricted by the minimum rock covers. On the basis of domestic and foreign literature about subsea tunnel, the numerical methods which could obtain the minimum rock covers of the subsea tunnel were discussed. In the numerical method, using damage-fracture model and numerical analytical software, the displacement convergence criterion for the minimum rock covers of the subsea tunnel was developed. Namely, the displacement convergence condition and the allowable displacement value were discussed at the same point above the tunnel for the same cross section at the different bottom floor position. The basic idea of the numerical method to obtain the minimum rock covers of the subsea tunnels was given by investigation of two subsea tunnels. The minimum rock covers of the subsea tunnel could be determined by numerical analysis quantitatively.