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The design of tunnels requires the proper prediction of surface settlements for estimating the potential impact on adjacent structures. In computational methods, accurate prediction of the tunnelling-induced surface settlements should consider the features of the non-linear elastic soil behaviour, the tunnel deformation boundary condition and the tunnelling details. In this paper the tunnel-deforming mechanism is modelled by an analytical approach to account for the three different tunnel-deforming components, i.e. ground loss, ovalization and vertical translation. The deformation around the tunnel profile was shown to be highly non-uniform. Such a tunnel deformation model was then integrated into the numerical analysis to investigate how the influences affect the predicted surface settlement profile. The capacity and applicability of the proposed procedure were explored by means of a parametric study. Results indicate that a realistic tunnel-deforming pattern combined with a soil model that can take account of stiffness decay at small strains can lead to a more accurate prediction of tunnelling-induced settlement profiles. Modellierung von Oberflächensenkungen durch ungleichmäßige Verformungen eines Tunnels. Der Entwurf von Tunneln erfordert eine genaue Vorhersage von Oberflächensenkungen zur Abschätzung der möglichen Auswirkungen auf angrenzende Bauwerke. Im Rechenverfahren sollte eine genaue Vorhersage der durch den Tunnelbau hervorgerufenen Oberflächensenkungen die Eigenschaften des nichtlinearen, elastischen Bodenverhaltens, die Randbedingungen der Tunneldeformation und Einzelheiten des Tunnelbaus berücksichtigen. In dieser Arbeit wurde der Tunnelverformungsmechanismus durch eine analytische Herangehensweise dargestellt, um drei verschiedene Tunnelverformungskomponenten, d. h. Masseverlust, Ovalisierung und vertikale Translation, zu berücksichtigen. Die Verformung rund um das Tunnelprofil erwies sich als höchst uneinheitlich. Ein solches Tunnelverformungsmodell wurde dann in der numerischen Analyse angewandt, um die Auswirkungen der Einflussfaktoren auf das vorhergesagte Profil der Oberflächensenkung zu erforschen. Die Kapazität und die Anwendbarkeit des vorgeschlagenen Verfahrens wurden von einer Parameterstudie untersucht. Die Ergebnisse zeigen, dass ein realistisches Tunneldeformationsmuster zusammen mit einem Bodenmodell, welches Festigkeitsverlust bei kleiner Belastung berücksichtigen konnte, zu einer genaueren Vorhersage des durch den Tunnelbau verursachten Bodensenkungsprofils führen können. [ABSTRACT FROM AUTHOR]

Abstract: The integration of the Geographic Information System (GIS) and the numerical simulation for slope stability analysis is investigated in this paper. The powerful spatial analysis functions of GIS such as automatic profile generation and gridding of the digital elevation model (DEM) are used in the preliminary treatment of numerical modeling, and a program for transforming GIS data to a commercial finite difference code FLAC has been developed using FLAC''s built-in programming language, FISH. At last, for demonstrating the reliability of this technique, the stability analysis of Xuecheng slope in 2D and 3D is performed and discussed. The preprocessing of data using GIS software for slope numerical simulation leads to saving time and money besides providing the real world data for use in numerical modeling. [Copyright &y& Elsevier]

The excavation induced ground movements and their impact on adjacent buildings is one of the major concerns for tunnelling in urban areas. This paper presents a case study on the response of the ground and a group of buildings to the construction of a sprayed concrete lining (SCL) subway twin tunnel through completely weathered granitic residual soil in Shenzhen, China. Ground and nearby structures displacements were monitored through extensive field instrumentation. The observed maximum surface settlements exceeded 400 mm, which caused considerable damage to certain buildings. Potential risks of large ground deformation for tunnelling in similar ground condition, with structures nearby, are highlighted. Encouraging effectiveness of the permeable grouting on this ground condition was demonstrated by the distinct Greenfield behaviour at the two monitoring sections. Different responses between Greenfield ground and adjacent structures show an evident soil structure interaction. Piled reinforced concrete frame buildings were found to behave rigidly in response to the tunnelling induced ground movement and to be without visible crack in contrast to masonry wall structures. [ABSTRACT FROM AUTHOR]