For the study on mechanical behavior and cracking characteristics of tunnel linings, down scaled models were tested. The effects of considered parameters on the mechanical behavior were shown in terms of cracking load, failure load, critical section and finally load-deflection curve. Numerical algorithm were developed to analyze the behavior of the double lining as well as ground mass separately or simultaneously. Parametric studies and a case history gave the mechanism of cracks prone to occurrence in the vicinity of crown of concrete lining, and available methods to control the cracking.
Les modeles à l'echelle reduite ont ete employes dans l'etude sur le comportement mecanique et les caracteristiques de fissuration du revêtement de tunnel. Les effets des parametres consideres sur Ie comportement mecanique ont ete demontres en function de la charge de fissuration, de la charge de rupture, de la section critique et de la courbe charge-deflexion. Un algorithme numerique a ete developpe à fin d'analyser le comportement du revêtement en double comme du jerrain individuellement ou simultanernent. Les tudes parametriques et une etude des cas ont permis de savoir Ie mecanisme de fissuration plausible de se produire à proximite de couronne du revêtement en beton et les methodes disponibles pour contr ler la fissuration.
Fuer die Untersuchung auf dem mechanischem Verhalten und der Ri bildungeigenheit der Tunnelverkleidung, der Versuch in kleinem Ma stabe wurde angestellt. Die Einfluesse der ueberlegter Einflußgröße wurden im Begriff von der Ri ßbildungbelastung, der Bruchlast, dem kritischem Abschnitt, und der Kurve von Belastungablenkung angezeigt. Der numerisch Algorithmus wurde, um sowohl ein Verhalten von Doppelverkeidung als eine Gebirgmasse zu bestimmen, entwickelt. Die Studieren von der Einflußgröße und der Erfahrungsbericht gab den Mechanismus von Risse zu vorkommen in der Nahe der Betonverkeidungskrone, und die benutzbare Methode zu beherrschen die Rißbildung.
Model experiments with tunnel concrete lining models have been conducted by the way of applying the mechanical loads directly to the scaled models or carrying the loads through the ground materials indirectly to them [paul et al., 1983, Piede, 1986 & Asakura et al., 1990]]. They tried to show the relation of cracking and failure load, deflection, critical section, and resultant sectional forces for single lining models. Piede only had tested small double lining models but couldn't show the quantitative relations among parameters.
Numerical analyses including the interaction of soil and structure have been often performed to compare numerical results with in-sini monitoring data, and to investigate how to respond the lining model numerically due to the moderately supposed distribution of ground stresses [Piede, 1.986& El-Nahhas, 1992]. However, almost of them studied only single linings. As a result, they couldn't consider the interaction of shotcrete and concrete lining, and of surrounding ground mass and the concrete lining.
Mechanical cracking on the concrete linings has brought a need to study the role of the concrete lining in load-dividing practice between shotcrete and the concrete lining in case of losing completely the load carrying capacity of shotcrete as the first support system.