Shallow tunnels misaligned with geostatic principal stress directions: Analytical solution and 3D face effects

Vitali, Osvaldo P.M.; Celestino, Tarcísio Barreto; Bobet, Antonio

doi:10.1016/j.tust.2019.04.006

Cited by 22 publications

(6 citation statements)

References 25 publications

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“…6. The corrected radial displacements are asymmetric near the face, which is consistent with Vitali et al (2019b). The authors observed that the far-field axial shear stress caused asymmetric radial deformation near the face of a shallow tunnel in isotropic ground.…”

Section: Tunnel In Horizontally Structured Rock Masssupporting

confidence: 85%

“…The combination of rock anisotropy and far-field axial shear produces a response of the rock around the tunnel quite different (and more complex) than when the rock is isotropic. Indeed, in isotropic elastic ground, Vitali et al (2019b) observed that the asymmetric radial deformations near the face due to a far-field axial shear stress could be decomposed into a rigid body displacement of the tunnel cross-section and anti-symmetric radial displacements, which is not always the case in anisotropic rock.…”

Section: Tunnel In Vertically-structured Rock Massmentioning

confidence: 99%

“…When the tunnel is misaligned with the geostatic principal stress directions, far-field axial shear stresses are present. These axial shear stresses induce antisymmetric axial displacements and axial shear stresses farbehind the tunnel face (Vitali et al, 2018;2019a;2019b;2019c). On shallow tunnels in isotropic ground, Vitali et al (2019b) observed that the far-field axial shear stress induced asymmetric deformations and stresses near the face and that ground-support interaction and yielding around the tunnel, if any, were affected by the asymmetric deformations near the face.…”

Section: Introductionmentioning

confidence: 99%

“…These axial shear stresses induce antisymmetric axial displacements and axial shear stresses farbehind the tunnel face (Vitali et al, 2018;2019a;2019b;2019c). On shallow tunnels in isotropic ground, Vitali et al (2019b) observed that the far-field axial shear stress induced asymmetric deformations and stresses near the face and that ground-support interaction and yielding around the tunnel, if any, were affected by the asymmetric deformations near the face. Vitali et al (2019c) investigated the effects of tunnel misalignment on the progressive failure around the well-documented experimental tunnel at the URL in Canada (Martin, 1997).…”

Section: Introductionmentioning

confidence: 99%

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Tunnel Misalignment with Geostatic Principal Stress Directions in Anisotropic Rock Masses

Vitali¹,

Celestino²,

Bobet³

2020

S&R

Self Cite

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Rock masses may present pronounced stress anisotropy, and so it is likely that a tunnel is misaligned with the geostatic principal stress directions. As a consequence, anti-symmetric axial displacements and axial shear stresses are induced around the tunnel due to the presence of far-field axial shear stresses. Limited research has been conducted on the effects of far-field axial shear stresses on tunnel behavior. This paper investigates the effects of tunnel misalignment with the geostatic principal stresses in anisotropic rock masses. 3D FEM modeling of a tunnel misaligned 45°with the principal horizontal stresses is conducted. An anisotropic geostatic stress field is considered, with the major horizontal stress two times larger than the vertical stress and the minor horizontal stress equal to the vertical stress. The anisotropic behavior of the rock mass is represented by a transversely anisotropic elastic model, with properties typical of anisotropic rock masses. Tunnels in horizontally and vertically-structured rock masses are assessed. Unsupported and supported tunnels are investigated. The results show that asymmetric deformations and asymmetric stresses are induced near the face of the tunnel as a result of the tunnel misalignment with the geostatic principal stresses and with the rock mass structure. These asymmetric deformations near the face affect the ground-support interaction such that the internal forces in the liner are also asymmetric.

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Section: Tunnel In Horizontally Structured Rock Masssupporting

confidence: 85%

Section: Tunnel In Vertically-structured Rock Massmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tunnel Misalignment with Geostatic Principal Stress Directions in Anisotropic Rock Masses

Vitali¹,

Celestino²,

Bobet³

2020

S&R

Self Cite

View full text Add to dashboard Cite

show abstract

“…When σ H oblique with tunnel axis, the effect of initial shear stress to stress redistribution is difficult to simulate in twodimension stress field analyzing, resulting in a deviation with the actual simulation [32,58]. As an effective method, threedimensional stress field analysis by finite element approaches is applicable to solve the redistribution of σ θ on the boundary of a deep-buried-curve tunnel.…”

Section: Numerical Simulation Of Three-dimensional Stress Fieldmentioning

confidence: 99%

The Influence Mechanism of In Situ Stress State on the Stability of Deep‐Buried‐Curved Tunnel in Qinghai‐Tibet Plateau and Its Adjacent Region

Wang

Tan

Feng

et al. 2021

Shock and Vibration

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In China, rockburst disaster occurs mostly in construction of underground engineering in Qinghai-Tibet Plateau and its adjacent region. Previous research on deep-buried tunnels has indicated that tunnels stability is related to in situ stress state. To quantify these relationships, three-dimensional finite element modeling was done to analyze the influences that the angle φ between the maximum horizontal principal stress orientation and tunnel axis, and the lateral pressure coefficient KH, had on the tangential stress σ θ in a deep-buried-curved tunnel. Based on the in situ stress condition in Qinghai-Tibet Plateau and its adjacent region, 50 different simulation conditions were used to analyze the relationship that φ and KH had on σ θ for the rock mass surrounding the tunnel. With the simulation data produced, predictive equations were generated for σ θ as a function of φ and KH using multivariate regression analysis. These equations help estimate σ θ at various key positons along the tunnel boundary at Qinghai-Tibet plateau and its adjacent region. The equations were then proved by a set of typical tunnels to ensure validity. The results concluded that the change in φ has a significant impact on σ θ , and thus, the stability of the tunnel, when 30° < φ < 60°, with the most obvious influence being when φ is about 45°. With the equations, the rockburst potential at a certain location within a curved tunnel can be quickly estimated by calculating φ and KH on σ θ , without need of geo-stress background knowledge and heavy simulation, allowing for the practical value in engineering at design phase for the projects in Qinghai-Tibet Plateau and its adjacent region.

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Analytical Solution for a Deep Circular Tunnel in Anisotropic Ground and Anisotropic Geostatic Stresses

2020

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Shallow tunnels misaligned with geostatic principal stress directions: Analytical solution and 3D face effects

Cited by 22 publications

References 25 publications

Tunnel Misalignment with Geostatic Principal Stress Directions in Anisotropic Rock Masses

Tunnel Misalignment with Geostatic Principal Stress Directions in Anisotropic Rock Masses

The Influence Mechanism of In Situ Stress State on the Stability of Deep‐Buried‐Curved Tunnel in Qinghai‐Tibet Plateau and Its Adjacent Region

Analytical Solution for a Deep Circular Tunnel in Anisotropic Ground and Anisotropic Geostatic Stresses

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