Time-Dependent Modeling of Tunnels in Squeezing Conditions

Barla, Giovanni Battista; Debernardi, Daniele; Sterpi, D.

doi:10.1061/(asce)gm.1943-5622.0000163

Cited by 138 publications

(67 citation statements)

References 23 publications

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“…The load-displacement curve in Fig. 2 was determined in laboratory tests at the Politecnico di Torino [7]. It can be seen that the elements show high initial stiffness and after the "yield limit" has been exceeded, practically constant resistance over a large range of strain.…”

Section: Hidcon Systemmentioning

confidence: 99%

“…Arbeitslinie eines Beton-Stauchelements, aus [7] Tunnelling (Graz University of Technology) with the aim of optimising the load-displacement characteristics and energy absorption [9]. Particular attention was paid to matching the yielding elements to strength development, in particular that of young (still "green") shotcrete, and then a design aid was also developed.…”

Section: System Wabementioning

confidence: 99%

“…Die Arbeitslinie in Bild 2 ist durch Laborversuche an der Politecnico di Torino bestimmt worden [7]. Auffällig ist dabei, dass die Elemente eine hohe Anfangssteifigkeit aufweisen und nach Überschreiten der "Fließgrenze" mit anschließen-dem Abfall einen praktisch konstanten Widerstand über einen großen Dehnungsbereich zeigen.…”

Section: System Hidconunclassified

“…Das von der Bochumer Eisenhütte Heintzmann GmbH & Co.KG, Bochum, Deutschland, [8] vertriebene System Wabe besteht aus einer Gruppe quer zur Achse beanspruchter Stahlrohre, die untereinander mit Flachstahl verbunden [7] Bild 2. Arbeitslinie eines Beton-Stauchelements, aus [7] Tunnelling (Graz University of Technology) with the aim of optimising the load-displacement characteristics and energy absorption [9].…”

Section: System Wabeunclassified

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Yielding elements – requirements, overview and comparison / Stauchelemente – Anforderungen, Überblick und Vergleich

Moritz¹

2011

Geomechanics and Tunnelling

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Large deformations are usual for tunnel excavation in weak rock mass and high overburden. In order to avoid overloading the support, various ductile support systems have been developed in the last 15 years to permit the controlled build-up of load in the lining. The design of such a ductile support system requires the consideration of the development of displacements in space and time, the time-dependent properties of the shotcrete and the characteristics of the ductile elements. The requirements for a yielding system are described. The latest developments in yielding elements for use with shotcrete support are discussed and their general performance and effectiveness are explained.

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Section: Hidcon Systemmentioning

confidence: 99%

Section: System Wabementioning

confidence: 99%

Section: System Hidconunclassified

Section: System Wabeunclassified

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Yielding elements – requirements, overview and comparison / Stauchelemente – Anforderungen, Überblick und Vergleich

Moritz¹

2011

Geomechanics and Tunnelling

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“…The squeezing behavior observed in this access gallery has been analyzed in several studies, emphasizing the time-dependent behavior of the rock mass in the framework of viscoplasticity (Barla et al , 2010(Barla et al , 2011Pellet 2009) and damage mechanics (Ordaz 2008). However, in these models the anisotropic character of the convergences was not considered.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Time-Dependent Modeling of Tunnel Excavation in Squeezing Ground

et al. 2015

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Most of the viscoplastic models used to describe the constitutive behavior of squeezing grounds assume isotropic deformation. However, it is commonly observed that squeezing behavior is characterized not only by large time-dependent but also often by anisotropic deformations. This study uses a semi-empirical approach based on the analysis of convergence measurements and a numerical model that takes into account the time-dependent and the anisotropic response of the rock mass to investigate the squeezing behavior of the Saint-Martin-laPorte access gallery, excavated within the Lyon-Turin railway project. We first show how the semi-empirical convergence law of Sulem et al. (Int J Rock Mech Min Sci Geomech Abstr 24(3):155-164, 1987a; Int J Rock Mech Min Sci Geomech Abstr 24(3):145-154, 1987b) can be extended to anisotropic tunnel closure by considering an elliptical deformation of the rock mass and by fitting the convergence data along the principal axes of deformation. A new anisotropic time-dependent constitutive model is then proposed. This model includes ubiquitous joints of specific orientation embedded in an isotropic viscoplastic medium. This model is implemented in FLAC3D and numerical simulations are performed to back-analyze the anisotropic closure of the Saint-Martin-la-Porte accessgallery. An efficient two-step procedure for calibrating the model parameters is proposed: the parameters of the isotropic solid matrix are first estimated by performing axisymmetric numerical simulations. The parameters of the ubiquitous joints are then calibrated by performing 3D computations. It is shown that the numerical results reproduce very well the convergence measurements of the studied sections of Saint-Martin-la-Porte gallery.

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In situ creep tests on the long‐term shear behaviors of a fault located at the dam foundation of Dagangshan hydropower station, China

Yang

Kang

Zhang

et al. 2019

Energy Science & Engineering

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Faults in the rock mass of dam foundation are crucial in controlling dam deformation and stability. In particular, long‐term stability of dam foundation is an important factor for the safety of dam operations. The rock in the foundation of Dagangshan hydropower station is mostly granite, and there are many diabase dikes distributed in granite. Geological survey indicates that many faults exist along the interfaces between granite and diabase. Lots of diabase were metamorphosed to chlorites, which have very low strength. In order to investigate the deformation of faults in diabase dikes under long‐term loading, in situ shear creep tests were performed to estimate the creep performance of a fault. The shear creep displacement and the influence of displacement history of the specimen during multi‐level loading tests were measured and analyzed. The isochronous stress‐strain method was used to determine the long‐term strength of the fault in shear creep tests. Considering the instantaneous damage and strain softening, a new viscoelastic‐plastic softening creep model was proposed to describe the shear creep behavior of the fault. Comparisons confirmed that this creep model is capable of describing the shear creep behavior of the fault and the creep parameters were estimated accordingly using this model.

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Time-Dependent Modeling of Tunnels in Squeezing Conditions

Cited by 138 publications

References 23 publications

Yielding elements – requirements, overview and comparison / Stauchelemente – Anforderungen, Überblick und Vergleich

Yielding elements – requirements, overview and comparison / Stauchelemente – Anforderungen, Überblick und Vergleich

Anisotropic Time-Dependent Modeling of Tunnel Excavation in Squeezing Ground

In situ creep tests on the long‐term shear behaviors of a fault located at the dam foundation of Dagangshan hydropower station, China

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