Study On The Long Term Settlement Of Submerged Tunnel In Soft Clay Under Cyclic Loading

Rail transit in China is under rapid development in recent years, and submerged tunnel has become the first choice of traffic mode to connect both sides of river. However, due to the high water pressure and wave load, the soil around submerged tunnel behaves quite different from underground tunnel with traffic load. So far, the complicated work environment can be simulated by large finite element software, but the analytic solution still need to be addressed. The analytic solution of the settlement of tunnel under wave load and traffic load with partially permeable boundary was put forward in this paper based on the two-dimensional consolidation theory founded by Terzaghi and Rendulic, the given formula was draw by conformal transformation. Besides, it roundly analyze the long term settlement of the submerged tunnel with wave load and traffic load, the main work are as follows:(1) The two-dimension consolidation problem was solved in two-dimension ring domain through conformal transformation by equating the wave load with the pore pressure at the riverbed, and the Gibbs free energy and endochronic theory was used to calculate the cumulative pore pressure under cyclic wave loading, the analytic solution of consolidation at the bottom of submerged tunnel was derived with characteristics of the soil.(2)The analytic solution of consolidation with partially permeable boundary under wave load was derived, and analyzed the soil behavior with different water level and relative permeability rate.(3)The cumulative plastic deformation caused by traffic load was calculated as a part of settlement of the submerged tunnel, the long term settlement of the submerged tunnel can be worked out with the consolidation under wave load and water pressure.