Due to the increasing development of urban spaces, underground spaces are currently taken into consideration. Subway tunnels are one of these underground spaces which have been considered in development of urban transport. In this regard, one of the most challenging cases is dig of subway tunnels in shallow and soft ground. Therefore, it is important to perform stability analysis and select maintenance in various stages of construction in long term. This project studied twin tunnels of the subway passing through Isfahan Naqsh-e Jahan square by using numerical methods (finite difference method) and FLAC3D. Given that subway tunnels are constructed under historically important buildings, displacements caused by digging and ground level settlement are the main problems with digging shallow underground spaces. These and other important problems are influenced by the selected digging method for subway tunnels. For stability analysis, different types of maintenance systems were studied using stability criteria; finally, the proper maintenance system was selected. There are different methods for digging urban underground spaces in soil and beneath groundwater level. The methods used for preventing water penetration into large underground spaces can include drainage, chemical consolidation, injection, ground solidification, tunneling by closed shields and compressed air, which are used with regard to working conditions in digging underground spaces. The results obtained by numerical method were compared with allowable settlement of ground level buildings. Finally, the most suitable drilling method with proper maintenance was selected. Numerical modeling was performed for various distances; finally, 9 m distance was suggested. In comparison with all allowable values noted in this study, slope of ground settlement curve and the worst-case settlement (0.000608 and 1.34 cm, respectively) were within the allowable range.
کلید واژگان :subway twin tunnels, underground spaces, ground settlement, boring machine TBM, maintenance systems, FLAC3D
ارزش ریالی : 600000 ریال
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