| Abstract | As much as urbanization, transportation systems are crucial to consider in order to meet the demand for public transportation in huge and crowded cities. In the Bangkok downtown area, not only the aboveground space is very limited and blocked, but also the underground space is congested by the deep pile foundations, underground drainage systems, subways, substructures, etc. Consequently, close proximity tunneling cannot be evaded. Moreover, a system of parallel twin tunnels was often adopted at the beginning of underground tunnelling. Nowadays, as the number of metro lines grows, underground usage becomes intricate and complex. Therefore, a system of stacked twin tunnels is frequently selected to be designed and constructed. The proximity tunnelling of stacked twin tunnels system may cause significant structural integrity and excessive lining deformation of proceeding tunnel. Besides, the twin stacked tunnelling system may cause significant effects to adjacent existing pile foundations. In the study, an evaluation of the interactions between ground and twin stacked tunnels due to the proximity effect of the tunneling is discussed using the data obtained from the Mass Rapid Transit (MRT) projects. Empirical methods and Numerical analysis (PLAXIS 3D) are conducted. |