Determine the amount of the soil subsidence caused by tunneling near the former excavated tunnel

Tunnel excavating (tunneling) on soils make disturbing in strain and stress fields in its surroundings, which can cause irreparable damages to ground structures and installations. Recently many studies have carried out to estimating the subsidence of shallow tunnel excavation, but they did not consider much tunnel excavation near the (at the vicinity of) former excavated tunnel. In this paper, we investigated the ground subsidence level caused by tunnel excavation of Tehran No. 3 subway line. For this, a numerical model is being built based on the information of the ground level behavior after the excavation in which we can estimate surely the subsidence of tunnel excavation in its surroundings. In this survey, the parameters tunnel diameters and their distance from each other and the overload on the tunnels were used as variables and the constant parameters are the soil specific weight, Poisson ratio, elastic module, inner angel fraction and the dilation angel. Moreover, we used the Mohr–Coulomb theory for the soil around the tunnel and the tunnel structures. We also used the reported data for validating the measurement and the model geometry was simulated in the Plaxis 3D Tunnel software. Finally, various models were indicated in respect to the variable and constant parameters and the analysis will be provided based on the outputs (Optimal distance between two tunnels and the relation of tunnel subsidence level with overload pressure caused by the soil and nearby buildings).

کلیدواژه ها:

Subsidence ، Numerical model ، Plaxis 3D Tunnel ، Constant parameters ، Tehran No.3 subway line ، Mohr–Coulomb theory