عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Due to the importance of tunnels in urban transport network and their increasing development, their design or construction is always faced with new technical problems or concerns. One of these concerns is the effect of dynamic loads generated by the movement of the train on the tunnel. The goal of this research is to provide the stability analysis of a section of the tunnel of line 3 of Tehran metro by three dimensional (3D) numerical modeling.
By increasing the urban population, construction and development of urban infrastructures are becoming more essential. Construction and development of subway tunnels in urban areas have always been facing with serious restrictions and problems. One of the problems, investigated in this research, is the intersection of subway lines with railway lines. The purpose of this research is to provide a proper method for construction of some parts of the tunnel of line 3 of Tehran subway passing below the global railway lines of Tehran-Ahwaz.
Methodology and Approaches
In the initial design stage, a part of the tunnel of line 3 of Tehran was designed using cover and cut method and by considering its technical advantages in implementation and reduction of costs, and thus, the cover and cut method was suggested for implementation of the project. In order to analyze the stability of this part of tunnel, the dynamic load due to the motion of a train was applied in the simulation process, and as a result, a function for the dynamic load of this motion was obtained. This function was applied in the built numerical model of the tunnel by FLAC 3D software. Then, the obtained results of modelling was compared with two analytical methods to determine the stability of the tunnel using velocity of the train, weight of the wagon, number of the wagons and damping in the environment in the most critical situations.
Results and Conclusions
The accomplished analyses in this research suggest that the tunnel stability is in an acceptable condition, and there is no need to reinforce the support system. Furthermore, considering the need to expedite the construction and restoring railway on the tunnel, the cover and cut method has been suggested to implement the project.