Effect of Poisson's ratio on the normalized radial displacements occurring around the face of a circular tunnel

✍ Scribed by T. Unlu; H. Gercek

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 144 KB
• Volume: 18
• Category: Article
• ISSN: 0886-7798
• DOI: 10.1016/s0886-7798(03)00086-5

✦ Synopsis

The distribution of displacements occurring around the advancing face of a tunnel is one of the widely discussed topics in tunnelling. Unavailability of a closed-form solution for this problem has directed the researchers to the utilization of numerical analyses mainly. In this study, a three-dimensional finite difference stress analysis program, i.e. FLAC , has been employed for 3D determining the variation of radial boundary displacements along the longitudinal direction of a circular tunnel located in a hydrostatic in situ stress field. According to the results for a linear elastic material behavior, the normalized radial displacements occurring in the vicinity of the face are affected by Poisson's ratio of the surrounding medium. In addition, it has been noted that, depending on Poisson's ratio, the value of elastic pre-deformation occurring at the face ranges between 20 and 30% of the final tunnel deformation occurring far from the face. Furthermore, expressions obtained by non-linear curve fitting are presented for the normalized radial displacements occurring ahead of and behind the excavation face of the tunnel.