Close proximity tunnelling and measures adopted in MRTA Orange Line – East project

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. Consequently, proximity tunnelling cannot be evaded. Furthermore, since the number of metro lines grows and underground usage becomes intricate, a system of stacked twin tunnels is frequently selected to be designed and constructed. The proximity tunnelling of the stacked twin tunnel system may cause significant structural integrity and excessive lining deformation of proceeding tunnel. In this paper, an evaluation of the close proximity tunnelling was conducted by using empirical analysis and numerical modelling. The empirical analysis was conducted using Peck’s Ground Distribution Curve, and the numerical modelling was conducted using the PLAXIS 3D program. Comparison of the results obtained from both analyses was discussed in the paper.