THE INFLUENCE OF DEGRADATION OF SHEAR MODULUS OF SOIL ON PREDICTED RAILWAY VIBRATIONS IN TUNNELS EXCAVATED WITH TBM: A NUMERICAL ANALYSIS

Abstract eng:
In this paper the influence of the stress state within the soil on predicted railway vibrations in tunnels is studied, regarding Gs modulus degradation that occurs when the tunnel is excavated with Tunnel Boring Machine (TBM). The adopted procedure is uncoupled, using a 2D FEM model to simulate the process of tunnelling which incorporates the constitutive model known as Hardening Soil with small strain stiffness (HS-small). The Gs modulus values are then used in a dynamic numerical model based on a 2.5D FEM-PML approach in order to simulate the vibrations induced by railway traffic. Simulations are then performed assuming two different scenarios for the elastic properties of the ground: i) assuming Gs modulus for low strain deformation for whole domain, i.e., neglecting the perturbation of the soil due to the tunnel construction; ii) assuming values of Gs modulus computed taking into account the strains induced by the tunnel construction. The numerical results show a clear influence of tunnelling process, being more relevant at closest distances to the tunnel.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket