University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Gregor Idinger
(2010):
Centrifuge model tests and numerical analysis on the face support of shallow tunnels in dry sand.
Master / Diploma Thesis - Institut für Geotechnik (IGT),
BOKU-Universität für Bodenkultur,
pp 150.
UB BOKU
obvsg
- Abstract:
- Due to the increase in urbanization and a simultaneous decrease in available land all over the world, engineers are forced to place the required transportation and underground utility systems into the underground. Due to accessibility, tunnels for these infrastructures are constructed close beneath the ground surface. With many tunnels built in these usually soft ground conditions, not able taking a load, it is important to have a comprehensive understanding of the induced ground displacements and stresses and their impact on nearby structures. For a successful tunneling process, stability is achieved by applying a supportive pressure to the tunnel front. Determining the necessary support pressure is a big issue on concerns of safety and the damage which could be caused by the ground collapse of a shallow tunnel to surface structures. Although tunneling technology has significantly advanced in the past few decades, engineers are often relying on inaccurate empirical methods. Numerical modelling allows conducting more realistic analyses that take into account the tunnel-lining interaction, construction sequence and three-dimensional face effects. For validation of these models, ground response to tunneling has to be studied using small-scale models. In this thesis, the influence of the overburden was investigated in a geotechnical centrifuge, which allows investigations in a true stress field. A tunnel model specially designed for this thesis enables the measurement of the required support pressure with a load cell. Soil deformations and surface settlements in the observable longitudinal tunnel section are documented. The required support pressure and ground deformations caused by the loss of face support have been compared to already existing investigations.
- Beurteilende(r): Wu Wei