Three-dimensional nonlinear analyses of a metro tunnel in Sao Paulo porous clay

• Type: Article in International Scientific Journal
• Date: 2011

Authors

Manuel Matos Fernandes (Author) FEUP

Journal

Title: Journal of geotechnical and geoenvironmental engineering

Vol. 137 No. 4

Pages: 376-384

ISSN: 1090-0241

Publisher: ASCE-AMER SOC CIVIL ENGINEERS

Other information

DOI: 10.1061/(ASCE)GT.1943-5606.0000433

Abstract (EN): Tropical residual clays with a highly porous structure react to the stress changes induced by tunneling in such a way that surface settlements can be larger than crown-level settlements along a tunnel axis. This behavior, which is not readily simulated by most numerical analyses, was also observed in the Paraiso tunnel, built for the São Paulo Metro, Brazil. This is a shallow tunnel driven through porous clayey soils by the sequential method. Detailed results of field monitoring are presented and discussed. 3D finite-element analyses that allowed a detailed simulation of the construction sequence have been carried out, considering two distinct constitutive models for the soil: a simple elastic-perfectly-plastic Mohr-Coulomb model, and the elastoplastic model developed by Lade. The results of these analyses are compared with the observed behavior as well as with the results from a plane strain finite-element analysis. It is shown that only the 3D finite-element analysis coupled with the more sophisticated soil constitutive model provides a full reproduction of field performance, with particular relevance for the deformations in the soil mass over the tunnel. © 2011 American Society of Civil Engineers.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9