3-D FEM Emulation Computation on Surrounding Concrete of Steel Spiral Case Keeping Internal Pressure during Construction

The surrounding concrete of steel spiral case in the power station of Three Gorges Project is constructed by means of keeping a specific level of internal pressure during construction. For analyzing the contact behavior of the interface between the steel spiral case and its surrounding concrete, the numerical simulations according to the actual construction procedure are carried out with 3-D FEM. The variation of the gap and the interaction force between the steel spiral case and its surrounding concrete in different operation stages and different seasons are put forward. It is concluded that: the circumferential force of inner face for the surrounding concrete is relatively big under the loads of internal water force and temperature, which should be considered in the structure design; the interaction force in summer is bigger than in winter; the deformation of the steel spiral case during the process of increasing the internal pressure need to be pay attention to. By comparing the emulation computation results with the prototype safety monitoring data during and after the constructing of surrounding concrete, we can see that they are in good agreement. The method and the program are proved to be feasible.