Study On Pipe Settlement And Strain Of Undersea Immersed Tube Tunnel

With the increasing maturity of the immersed tube tunnel technology, more across river (sea) project selected immersed tube construction method. However, as a special underwater tunnel, uneven subsidence and deformation of the pipe section will cause pipe cracking, leakage, etc, directly affect the life and safety of the tunnel, hi this paper, analysis the immersed tube tunnel settlement in-depth through theoretical derivation and finite element simulation; research immersed tube tunnel section deformation through measurement. The main innovation of this paper and conclusions are as follows:(1) Based on the revised elastic foundation beam method, improved methods of K values and joint constraint, to make it more realistic project, put forward a new calculation method of immersed tunnel longitudinal differential settlement method. Taking Zhoushan Shenjiamen port undersea immersed tunnel as an example, makes a detailed analysis of the example.(2) The immersed tunnel and foundation soil base layer is defined as the overall composite foundation, with a spring on behalf of the base layer, Kelvin model represents the soil, proposed three-parameter model to simulate composite foundation. On the basis of solution of the beam on elastic foundation, according to the correspondence principle and the three-parameter model constitutive relations, use the Laplace transform, deduced the three-parameter analytic solutions of the settlement of immersed tunnel.(3) Assuming the undersea immersed tunnel foundation in soft soil area is Kelvin model, vehicle load is fluctuating with time, and introducing viscoelastic foundation beam model. Answer the vertical displacement, bending moment and ground reaction force in three different cases using modal superposition method. Contrasting of Tianjin Haihe River immersed tunnel project, analysis the impact of vehicle speed, foundation soil modulus on the vertical displacement and bending moment of the tunnel.(4) The strain of pipe section of Zhejiang province in a sea of the immersed tunnel engineering was monitored by the fiber grating sensor. The testing data was analyzed and the section measured strain values of the measuring-point changing with time and the influence of tidal load on monitoring results were studied.(5) Using Midas GTS software realistic simulate Zhoushan Shenjiamen Habor underwater immersed tunnel in three-dimensional, obtained the deformation and stress of the section, and the corresponding results of each cross section settlement, then compare with the measured value.