Numerical and empirical analysis of face pressure effect on surface subsidence at a tunnel excavated by EPB method

In recent decades, metro tunnels are increasingly being excavated in Tehran. In these tunnel excavations, it is important to control surface settlements observed during and after tunneling excavation. Some empirical relations exist between shield tunnel characteristics and surface deformations. Also, 2-D and 3-D numerical analyses have been applied to such tunneling problems. This paper reports the results of a study carried out to estimate the values of the surface settlements induced by tunneling (with EPB) of the new extension of Tehran metro (line7). It is aimed at investigating the effect of face pressure on surface settlements during excavation by using empirical formulations and numerical modeling. Due to the structural features and geology of the area, finite difference method was selected and FLAC3D software was used for numerical modeling. The results obtained from the numerical and empirical analyses show that face pressure is very effective on controlling the surface settlement. The results are presented in the paper and provisions for reducing the settlement are discussed.

کلیدواژه ها:

Earth pressure ، Surface settlement ، Empirical methods ، FLAC 3D