عنوان مقاله [English]
In this paper, train induced tunnel-structure interaction problem is analyzed using the coupled scaled boundary finite element (SBFE)-finite element (FE) method. Scaled boundary is a relatively novel method, which is capable of modeling bounded and unbounded domains accurately. Effects of adjacent buildings and effects of double tunnel on train-induced vibrations are evaluated.
Construction and development of underground transportation lines like metro tunnels in urban areas is a suitable choice to reduce volume of the traffics especially in large cities. Train induced vibrations in these tunnels can be affected by adjacent structures. Train induced vibrations can make some damages in adjacent structures, and also, adjacent structures can affect vibrations of the tunnels. To analyze train induced vibration problems numerically, a special numerical method should be used to model unbounded soil media. Some of these methods are global and the others are local. Local methods cannot model radiation-damping effect of unbounded soil media completely and accurately. SBFE method is a global approach with semi-analytical formulation, which can model unbounded media precisely. In this paper, this novel approach is used to analyze tunnel- structure interaction problem.
Methodology and Approaches
In this paper, the coupled SBFE-FE method is used to model train-induced vibration in tunnels. The semi-analytical SBFE method is used to model unbounded soil media where conventional FE method is used to model near field soil media and contained structures. To use the mentioned coupled method, a MATLAB code is developed by the authors of this paper. The written code is verified by comparing its results with the results of the finite element-boundary element method presented in the relevant papers. As train induced vibrations cannot make large displacements, linear elastic behavior is considered for both soil and structures.
Results and Conclusions
It has been shown that adjacent buildings can make an increment on displacement time history of tunnels and it can reduce radiation-damping effect of the considered soil media. In the case of double tunnel, it is shown that adjacent tunnel can increase horizontal dynamic stiffness of the trapped soil between two tunnels. It is also demonstrated that the simultaneous movement of the second train can magnify the vertical displacements of the domain. In the case of the horizontal displacement, it is shown that the displacements of the domain between the two tunnels are decreased but the displacements of the other areas are magnified.