The concrete liners of existing tunnels could present relevant damages due to their ageing or weathering, or to improper construction techniques. In some cases, depending on the geological conditions, these faults are due to the overstress caused e.g. by the occurrence of landslides, by swelling or creep of the rock mass, etc. Whilst two-dimensional numerical models are in most cases sufficient to assess the stress-strain state within the liner, a proper analysis of its replacement should be based on three-dimensional calculations. They, in fact, permit evaluating the need of soil/rock treatments around the tunnel and the length of the tunnel portions in which the liner demolition and re-construction can be safely carried out. In addition, they are necessary for a proper design of the new reinforced concrete support. Three level of tunnel rehabilitation are discussed, ranging from light repairs of the inner surface of the liner to heavy structural changes involving its demolition and reconstruction. Some case histories related to highway tunnels are also presented that illustrate the mentioned levels of rehabilitation.
A consistent approach to the structural rehabilitation of tunnel liners
GIODA, GIANCARLO;
2004-01-01
Abstract
The concrete liners of existing tunnels could present relevant damages due to their ageing or weathering, or to improper construction techniques. In some cases, depending on the geological conditions, these faults are due to the overstress caused e.g. by the occurrence of landslides, by swelling or creep of the rock mass, etc. Whilst two-dimensional numerical models are in most cases sufficient to assess the stress-strain state within the liner, a proper analysis of its replacement should be based on three-dimensional calculations. They, in fact, permit evaluating the need of soil/rock treatments around the tunnel and the length of the tunnel portions in which the liner demolition and re-construction can be safely carried out. In addition, they are necessary for a proper design of the new reinforced concrete support. Three level of tunnel rehabilitation are discussed, ranging from light repairs of the inner surface of the liner to heavy structural changes involving its demolition and reconstruction. Some case histories related to highway tunnels are also presented that illustrate the mentioned levels of rehabilitation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
