What is the contribution of time-dependent deformation in tunnel convergence?

✍ Scribed by Villy Kontogianni; Panos Psimoulis; Stathis Stiros

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 98 KB
• Volume: 82
• Category: Article
• ISSN: 0013-7952
• DOI: 10.1016/j.enggeo.2005.11.001

✦ Synopsis

Tunnel excavation produces stress changes to the ground and strain to the support lining, leading to the closure (convergence) or instability of the excavated area. Convergence recorded after section excavation is assigned to: (i) strain resulting from the progressive tunnel front advance (face advance effect) and (ii) the time-dependent properties of the soil material (ground creep effect). In the present study, based on the geodetic monitoring records of two recent road tunnels in Greece, a simple methodology to estimate the contribution of each of the two effects is presented. Our analysis reveals that at least half of the total deformation of the examined tunnel sections is due to ground creep, indicating that the major portion of tunnel deformation is due to the timedependent properties of the ground; a result supported by previous studies from other tunnels as well.