Safety factor calculations of a tunnel face reinforced with umbrella pipes: A comparison analysis

Qian, Ze-Hang; Zou, Jinfeng; Pan, Qiujing; Dias, Daniel

doi:10.1016/j.engstruct.2019.109639

Cited by 37 publications

(9 citation statements)

References 29 publications

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“…In simulations, the implantable beam element was selected to simulate the pipe‐roof steel pipe, and the solid element was used to simulate the soil in the pipe‐roof reinforced area. The thickness of the reinforcement area was 1 m (Hisatake & Ohno, 2008; Z. Qian et al, 2019; P. Shi et al, 2018; X. Yang & Li, 2018).…”

Section: Establishment Of Numerical Simulationmentioning

confidence: 99%

Dynamic evolution in mechanical characteristics of complex supporting structures during large section tunnel construction

Hua

Jinxun

et al. 2022

Deep Underground Science and Engineering

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The shallow tunnelling method (STM) often uses temporary supports to divide large section tunnels into several closed or semiclosed sections so as to share the upper load. The complex support system composed of primary and temporary supports can ensure safety during tunnel construction. Based on the large section tunnel of Beijing Subway Line 12, the mechanical characteristics of support system by the double-side-drift method (DSDM) during excavation and demolition were analyzed through numerical simulation and monitoring. The study showed that the middle cave excavation was the most critical stage of the DSDM, during which the load on the supporting structure increased significantly. The temporary vertical support bore most of the new load during middle cave excavation. During the demolition stage, the load was redistributed, which caused arch settlement and section convergence. The removal of the temporary vertical support exerted the greatest impact in this process. The lateral temporary inverted arch changed from axial compression to axial tension after the middle and lower caves were excavated. Based on the mechanical characteristics of the support system, some engineering suggestions were proposed for large section tunnel construction. These research results can provide reference for the design and construction of similar large section tunnels.

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Section: Establishment Of Numerical Simulationmentioning

confidence: 99%

Dynamic evolution in mechanical characteristics of complex supporting structures during large section tunnel construction

Hua

Jinxun

et al. 2022

Deep Underground Science and Engineering

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“…Based on the proposed failure model, the limit support pressure of the tunnel face can be derived by equating the work rate exerted by external force to the internal energy dissipation rate using the upper-bound limit analysis method [21][22][23][24][25], which described by Equation (8). Note that the external forces in this study mainly include the supporting pressure at the tunnel face and the rock gravity.…”

Section: Work Rate Calculationsmentioning

confidence: 99%

Stability Analysis of the Horseshoe Tunnel Face in Rock Masses

Zhang

Liu

et al. 2022

Materials

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Accurately estimating the stability of horseshoe tunnel faces remains a challenge, especially when excavating in rock masses. This study aims to propose an analytical model to analyze the stability of the horseshoe tunnel face in rock masses. Based on discretization and “point-by-point” techniques, a rotational failure model for horseshoe tunnel faces is first proposed. Based on the proposed failure model, the upper-bound limit analysis method is then adopted to determine the limit support pressure of the tunnel face under the nonlinear Hoek–Brown failure criterion, and the calculated results are validated by comparisons with the numerical results. Finally, the effects of the rock properties on the limit support pressure and the 3D failure surface are discussed. The results show that (1) compared with the numerical simulation method, the proposed method is an efficient and accurate approach to evaluating the face stability of the horseshoe tunnel; (2) from the parametric analysis, it can be seen that the normalized limit support pressure of the tunnel face decreases with the increasing of geological strength index, GSI, Hoek–Brown coefficient, mi, and uniaxial compressive strength, σci, and with the decreasing of the disturbance coefficient of rock, Di; and (3) a larger 3D failure surface is associated with a high value of the normalized limit support pressure.

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“…Qian et al [51] combined the strength reduction method and the kinematic approach of limit analysis and used a three-dimensional model based on FEM to study the e ects of the length and elevation angle of pipes on the stability of the tunnel face. ey evaluated the failure of the surrounding rock by analyzing the size of the plastic zone.…”

Section: Coupling E Ect Of Support Structure and Surroundingmentioning

confidence: 99%

Study on Instability Mechanism and Support Scheme of the Tunnel Face in Carbonaceous Phyllite Stratum under High Geo‐Stress

Song

et al. 2022

Advances in Civil Engineering

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The tunnel face collapses easily during tunnel construction in weak surrounding rock under high geo-stress. Identifying the instability mechanism of the face and proposing targeted control measures are of great importance to prevent the collapse of the face. Using the setting of the carbonaceous phyllite stratum of the Baima tunnel, a FLAC3D-PFC3D coupled model is used to analyze the influential factors on the stability of the face and optimize the original support scheme. The results show that the instability of the face is rooted in the collapse of the rock above the face, and the bench method with short cycle footage is more conducive to the stability of the face. Compared with single support mode of advanced small pipes, the combined support scheme of long bolts and small pipes can better control the displacement of the surrounding rock and prevent the collapse of the tunnel face. The numerical simulation and field surrounding rock monitoring results verify the rationality of the excavation method, the cycle footage, and the support system. This finding will be of great significance to guide design and construction in weak surrounding rock.

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Safety factor calculations of a tunnel face reinforced with umbrella pipes: A comparison analysis

Cited by 37 publications

References 29 publications

Dynamic evolution in mechanical characteristics of complex supporting structures during large section tunnel construction

Dynamic evolution in mechanical characteristics of complex supporting structures during large section tunnel construction

Stability Analysis of the Horseshoe Tunnel Face in Rock Masses

Study on Instability Mechanism and Support Scheme of the Tunnel Face in Carbonaceous Phyllite Stratum under High Geo‐Stress

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