Subsidence prediction for twin tunnels using empirical formula – A case study: Isfahan, Iran.

In the urban tunneling project, one of the most important parameters to be considered is the subsidence level. Metro tunnels are one of the most important urban transportation infrastructures. Due to shallow depth of drilling, the most important factors to prevent the maximum subsidence and subsequent damage of surface and subsurface structures are deformation control and shear forces. The various methods of estimating the subsidence are divided in three categories, namely; Empirical, analytical and numerical methods. In this research, according to the geotechnical conditions of the study area using the data collected from the monitoring during the excavation of twin tunnels of metro by TBM, the empirical methods for the subsidence ( s=A_2+s_max/2 ), the maximum subsidence (s_max=A_1-A_2 ) and the inflection point (ⅈ=x_0 ) are presented by using Boltzmann function for Isfahan twin metro tunnel.