Effect of the Location of Liquefiable Sand Lenses on Shallow Tunnels During Earthquake Loading

• Published in: Arabian Journal for Science and Engineering Vol. 37; no. 3; pp. 575 - 586
• Main Authors: Mir Mohammad Hosseini, S. M., Azadi, M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.04.2012
• Subjects: Asymmetry; Deformation; Engineering; Humanities and Social Sciences; Lenses; Liquefaction; multidisciplinary; Position (location); Research Article - Civil Engineering; Sand; Science; Seismic phenomena; Tunnels (transportation); Sand lens; Shallow tunnel; Earthquake; Liquefaction
• ISSN: 1319-8025; 2191-4281
• DOI: 10.1007/s13369-012-0192-7

Loose sand lenses form due to geological processes and become saturated after a long period. The existence of such lenses around a tunnel may affect the forces and deformations in the tunnel lining. Modeling should be implemented in three spatial dimensions owing to asymmetrical conditions. Therefore, with a focus on loose sand lens in dense soil, this paper evaluates the effects of sand lens liquefaction on forces and deformations of the tunnel lining and surface settlement. Considering liquefaction analysis capabilities and the asymmetrical condition of the problem, Flac-3D software was employed. The present work focuses on the effect of the liquefiable sand lens on a shallow tunnel during earthquake loadings. It was found that the location of the sand lens greatly affects the behavior of underground structures. When the asymmetrical deformations and distortion of the tunnel lining are considered, the ratio of the dynamic state moment to the static state moment increases with the ratio of the sand lens distance to the tunnel diameter, and surface displacement decreases with increasing depth of the sand lens.