Impact of Advance Rate on Entrapment Risk of a Double-Shielded TBM in Squeezing Ground

Hasanpour, Rohola; Rostami, Jamal; Barla, Giovanni Battista

doi:10.1007/s00603-014-0645-2

Cited by 30 publications

(9 citation statements)

References 15 publications

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“…This model is implemented in FLAC 3D and has been previously used in many numerical simulations (e.g. Barla et al 2007, 2011, Pellet 2009, Sharifzadeh et al 2013, Hasanpour et al 2015.…”

Section: Monitoring Data and Data Processing In The Safety Gallerymentioning

confidence: 99%

Tunneling in Squeezing Ground: Effect of the Excavation Method

et al. 2019

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Tunnel excavation in squeezing ground exhibits large time-dependent and often anisotropic deformation. Within the context of the Fréjus road tunnel and its safety gallery excavated under the Alps between France and Italy, an interesting configuration of two parallel tunnels under squeezing ground conditions is observed. The special feature of this case study lies in the fact that both tunnels have been excavated in similar geotechnical conditions but with different excavation techniques. The road tunnel was excavated with conventional drill and blast methods in the seventies whereas the safety gallery was excavated between 2009 and 2016 with a single shield Tunnel Boring Machine (TBM).The present paper presents monitoring data processing and numerical simulations of both tunnels with the aim of studying the influence of the excavation method on the timedependent tunnel response. A calibration of a visco-elasto-plastic anisotropic constitutive model based on the back-analysis of convergence measurements retrieved during the excavation of the Fréjus road tunnel is carried out. The identified ground behavior can be extrapolated to the parallel zones of the safety gallery. In particular, we are interested in the prediction of the stress state in the segmental lining of the gallery during its excavation and the comparison with in situ measurements. It is shown that the time-dependent behavior of the ground is affected by the excavation technique. Finally, an attempt to predict the long-term response of both tunnels is proposed.

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“…This model is implemented in FLAC 3D and has been previously used in many numerical simulations (e.g. Barla et al 2007, 2011, Pellet 2009, Sharifzadeh et al 2013, Hasanpour et al 2015.…”

Section: Monitoring Data and Data Processing In The Safety Gallerymentioning

confidence: 99%

Tunneling in Squeezing Ground: Effect of the Excavation Method

et al. 2019

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“…Generally, the Young's modulus of rock mass was often assumed to be uniform in the ground reaction analyses (Graziani et al, 2005;Hasanpour et al, 2015). However, it was observed that the Young's modulus around an excavation was not constant, but rather non-uniform (Zhang et al, 2012;Cai et al, 2015).…”

Section: Relation Of Confining Pressure and Young's Modulusmentioning

confidence: 99%

“…For a general excavation, the confining pressure (minor principal stress) acting on the excavation surface is zero. It increases gradually with the increasing distance between the element and the excavation surface, and will reach a constant value at locations far away from the excavation (Carranza et al, 1999;Hasanpour et al, 2015). Hence, it is necessary to consider the stress field change in the rock mass surrounding the excavation to accurately predict the ground response, especially in deep buried excavations.…”

Section: Introductionmentioning

confidence: 99%

Influence of confining pressure-dependent Young’s modulus on the convergence of underground excavation

Jiang

Guan

et al. 2019

Tunnelling and Underground Space Technology

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The actual convergence of an excavation located in fractured rock mass or the soft rock is largely different with the theoretical result in many cases. Experimental results showed that the influence of confining pressure on Young's modulus is very significant. This paper attempted to illustrate the influence of the confining pressure-dependent Young's modulus in the ground reaction analyses of mountain tunnel. Firstly, the relationship between Young's modulus and confining pressure was described as a non-linear function according to the test results. Based on the plane strain axial symmetry assumption and the incremental theory of plasticity, equilibrium equations and compatibility equations of rock mass around a circular tunnel were deduced theoretically. Based on fourth Runge-Kutta method, a semi-analytical solution was achieved. Considering the effect of confining pressure on Young's modulus, the stress and deformation of rock mass around tunnel was calculated by both analytical and numerical methods. The influence of confining pressure-dependent Young's modulus in surrounding rock was estimated quantitatively. Finally, Tawara saka Tunnel in Japan was taken as an example to explain the influence of confining pressure-dependent Young's modulus. The results showed that the error with respect to the monitoring data was largely reduced with the confining pressure-dependent Young's modulus model, which indicated the necessity of considering the non-uniform distribution of Young's modulus.

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“…The goal of the present study is to approach the problem of estimating F f from several sides. It is emphasized that this study considers the topic of shield friction in non-squeezing, hard rock conditions (for squeezing conditions, see, e.g., Hasanpour et al (2014); Hasanpour et al (2015); Hasanpour et al (2018); Mohammadzamani et al (2019); Anagnostou (2010, 2011); Zhang and Zhou (2017)). First, theoretical considerations on the interaction between a TBM's shield and the surrounding rock mass are presented (Sect.…”

Section: Introductionmentioning

confidence: 99%

On the Effect of Shield Friction in Hard Rock TBM Excavation

Erharter

Goliasch²,

Marcher

2023

Rock Mech Rock Eng

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During hard rock tunnel boring machine (TBM) excavation, shields behind the cutterhead are usually in direct contact with the tunnel wall and therefore subjected to friction forces that occur within this interface. The effect of shield friction in hard rock TBM tunneling has received little attention so far and literature on this topic is scarce and conflicting. To investigate the friction coefficient for the planning of TBM excavations, specialized shear tests were conducted where steel specimens were sheared against lithologically different rock specimens under representative normal forces and shearing speeds. The tests were executed with and without the use of bentonite lubrication. The results show that there is a significant difference between different lithologies and also that using bentonite does not lower the friction coefficient as expected. To elaborate on the effect of shield friction during construction, a framework for interpretation of TBM operational data based on experience from construction sites is provided. Whereas thorough interpretation of the data enables one to draw conclusions about the shield friction, it still remains difficult to assess the real effect of shield friction due to the limited possibilities to observe the ongoing phenomena. This study therefore provides the basis for theoretical and practical assessments of the effect of shield friction for the planning and construction phase of a tunnel. This becomes increasingly important in the light of new contractual developments that aim at differentiating “standard” from “special” advance in an objective and reproducible way.

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Impact of Advance Rate on Entrapment Risk of a Double-Shielded TBM in Squeezing Ground

Cited by 30 publications

References 15 publications

Tunneling in Squeezing Ground: Effect of the Excavation Method

Tunneling in Squeezing Ground: Effect of the Excavation Method

Influence of confining pressure-dependent Young’s modulus on the convergence of underground excavation

On the Effect of Shield Friction in Hard Rock TBM Excavation

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