Effect of Poisson's ratio on the normalized radial displacements occurring around the face of a circular tunnel

Unlu, Tugrul; Gerçek, Hasan

doi:10.1016/s0886-7798(03)00086-5

Cited by 119 publications

(57 citation statements)

References 8 publications

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“…In practice, the determination of the LDP is often based on a finite element analysis using either axysimmetric or three-dimensional models, depending on the level of complexity of the tunnel geometry (i.e., circular versus non-circular shape), in-situ stress field (i.e., isotropic versus anisotropic), and material property distribution (i.e., homogeneous versus heterogeneous). Alternatively, analytical or numerical parametric solutions have been proposed for the cases of linear elastic (Panet, 1995;Unlu and Gercek, 2003) or elasto-plastic material behaviour (e.g., Panet and Guenot, 1982;Vlachopoulos and Diederichs, 2009). In the present study, the LDPs according to the method proposed by Vlachopoulos and Diederichs (2009) were adopted in an attempt to estimate the percentage of convergence that occurred before the simultaneous installation of the measuring targets and application of the shotcrete layer.…”

Section: Modelling Procedures For Excavation Advancementioning

confidence: 99%

The excavation of a circular tunnel in a bedded argillaceous rock (Opalinus Clay): Short-term rock mass response and FDEM numerical analysis

Lisjak

Garitte

Grasselli

et al. 2015

Tunnelling and Underground Space Technology

161

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a b s t r a c tThe Opalinus Clay formation is currently being investigated as a potential host rock for the deep geological disposal of radioactive waste in Switzerland. Recently, a test tunnel was excavated at the Mont Terri underground rock laboratory (URL) as part of a long-term research project (''Full-scale Emplacement (FE) experiment'') aimed at studying the thermo-hydro-mechanical (THM) effects induced by the presence of an underground repository. The objective of this paper is twofold. Firstly, the results of the rock mass monitoring programme carried out during the construction of the 3 m diameter, 50 m long FE tunnel are presented, with particular focus on the short-term deformation response. The deformation measurements, including geodetic monitoring of tunnel wall displacements, radial extensometers and longitudinal inclinometers, indicate a strong directionality in the excavation response. Secondly, the deformational behaviour observed in the field is analyzed using a hybrid finite-discrete element (FDEM) analysis to obtain further insights into the formation of the excavation damaged zone (EDZ). The FDEM simulation using the Y-Geo code is calibrated based on the average short-term response observed in the field. Deformation and strength anisotropy are captured using a transversely isotropic, linear elastic constitutive law and cohesive elements with orientation-dependent strength parameters. Overall, a good agreement is obtained between convergences measured in the field and numerical results. The simulated EDZ formation process highlights the importance of bedding planes in controlling the failure mechanisms around the underground opening. Specifically, failure initiates due to shearing of bedding planes critically oriented with respect to the compressive circumferential stress induced around the tunnel. Slippageinduced rock mass deconfinement then promotes extensional fracturing in the direction perpendicular to the bedding orientation. The simulated fracture pattern is consistent with previous experimental evidence from the Mont Terri URL.

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Section: Modelling Procedures For Excavation Advancementioning

confidence: 99%

The excavation of a circular tunnel in a bedded argillaceous rock (Opalinus Clay): Short-term rock mass response and FDEM numerical analysis

Lisjak

Garitte

Grasselli

et al. 2015

Tunnelling and Underground Space Technology

161

View full text Add to dashboard Cite

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“…The LDP is the graphical representation of displacements that occur along the axis of an unsupported excavation [51]. The LDP shows that a point within the rock mass, initially well ahead of the advancing roadway face, will have already experienced up to a third of its total displacement once coincident with the face [52]; this quantity is known as the pre-deformation [53]. Numerous equations exist that are used to estimate the LDP of radial displacements for circular tunnels [51,53,54], although they have also been used to estimate the LDP of an almost square tunnel [55].…”

Section: Measured Displacementsmentioning

confidence: 99%

“…The LDP shows that a point within the rock mass, initially well ahead of the advancing roadway face, will have already experienced up to a third of its total displacement once coincident with the face [52]; this quantity is known as the pre-deformation [53]. Numerous equations exist that are used to estimate the LDP of radial displacements for circular tunnels [51,53,54], although they have also been used to estimate the LDP of an almost square tunnel [55]. Figure 9 shows a possible LDP for the Thoresby Colliery roadway, depicting the profile of central roof displacements in relation to the location of the face.…”

Section: Measured Displacementsmentioning

confidence: 99%

Probabilistic analysis of a coal mine roadway including correlation control between model input parameters

Booth

Marshall

Stace

2016

Computers and Geotechnics

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk Abstract:Probabilistic analysis and numerical modelling techniques have been combined to analyse a deep coal mine roadway. Using the Monte Carlo method, a correlation control algorithm and a FLAC 2D finite difference model, a probability distribution of roof displacements has been calculated and compared to a set of measurements from an actual mine roadway. The importance of correlation between input parameters is also considered. The results show that the analysis performs relatively well, but does tend to over predict the magnitude of displacements. Correlation between parameters is shown to be very important, particularly between the three model stresses.

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“…The use of the LDP is also advantageous to the calculation of the GRC for jet grouted tunnels. Contrary to the longitudinal pressure variation, which has been derived essentially for elastic ground behavior [36], the LDP is provided by analytical, numerical, and empirical relations for a variety of ground behaviors including grounds with time-dependent behavior [21,22,[37][38][39][40][41]. One can also take into account the effect of tunnel supports by using implicit relations such as Eq.…”

Section: Conventional Vs New Approach For Grc Calculationmentioning

confidence: 99%

Ground reaction curve for tunnels with jet grouting umbrellas considering jet grouting hardening

Heidari

Tonon

2015

International Journal of Rock Mechanics and Mining Sciences

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Effect of Poisson's ratio on the normalized radial displacements occurring around the face of a circular tunnel

Cited by 119 publications

References 8 publications

The excavation of a circular tunnel in a bedded argillaceous rock (Opalinus Clay): Short-term rock mass response and FDEM numerical analysis

The excavation of a circular tunnel in a bedded argillaceous rock (Opalinus Clay): Short-term rock mass response and FDEM numerical analysis

Probabilistic analysis of a coal mine roadway including correlation control between model input parameters

Ground reaction curve for tunnels with jet grouting umbrellas considering jet grouting hardening

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