Authors:
Moamen Abd El Raouf; Khaled M. M. Bahloul;
Abstract:
Advancing TBM during tunnel construction induces a surface settlement, which affects the adjacent building and facilities. A three-dimensional finite element model (Plaxis 3D) was used to simulate and analyze this process. A comparison between the numerical model and field measurements of The Greater Cairo Metro (Line 3) was made to validate the results. Sensitivity analysis was carried out to determine how changes in some parameters affect the results of the finite element model like the constitutive models, the pile position relative to the tunnel axis, and the pile spacing. Three constitutive models (a Hardening Soil model with small strain (HSS), a Hardening Soil model (HS), and the Mohr-Coulomb model (MC) were used to evaluate the effect of the constitutive models on the results. From the numerical analysis, it can notice that the numerical results are in good agreement with the field measurements. The results obtained from the modelling (HSS) model are more realistic and closer to field measurement than the results obtained from the analysis using (HS) model, and the Mohr-Coulomb model (MC). Furthermore, the effect of the tunnel construction on the settlement of adjacent piles nearly vanishes at a distance of 2 D (D is the tunnel diameter. Finally, the increase in pile spacing decreases the impact of tunnel excavation on adjacent pile foundations.
Keywords:
Tunneling; Numerical model; Constitutive models, Pile foundation; Pile spacing.