Model test and numerical analysis for the face failure mechanism of large cross-section tunnels under different ground conditions

Sun, Zhenyu; Zhang, Dingli; Li, Ao; Liang, S.; Tai, Qimin; Chu, Zhaofei

doi:10.1016/j.tust.2022.104735

Cited by 42 publications

(9 citation statements)

References 46 publications

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“…The definition of the stress release rate at any point around the tunnel can be obtained by the ratio of the reduction in the constraint stress to the initial stress. The stress release rate is deduced as follows [27]:…”

Section: Stress Release Ratementioning

confidence: 99%

Research on Excavation Method for Soft Rock Tunnel Based on Stress Release Rate

Nie,

He,

Kou

et al. 2024

Applied Sciences

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A test method for controlling the stress release rate of the tunnel by adjusting the confining pressure is proposed based on the engineering background of Dongmachang No. 1 Tunnel of Huali Expressway to explore a suitable excavation method of soft rock tunnel. Based on the relationship between stress release rate, displacement release rate, and longitudinal advance of excavation face, the model test of tunnel excavation is carried out. On this basis, combined with the horizontal loading test and field monitoring results, the influence of three excavation methods, the three-bench method, three-bench with reserved core soil method, and three-bench seven-step method, on the mechanical behavior of the tunnel is studied. The research shows that the load shared by the double-layer initial support is not equal, and the second-layer initial support only bears 20% of the pressure of the first-layer initial support; replacing the three-bench method with the three-bench core soil method and the three-bench seven-step method can reduce the deformation of the surrounding rock by 8.7~12.4%, and the load borne by the supporting structure is transferred from the second layer to the first layer. In order to take into account the safety and efficiency of tunnel construction, it is recommended to use the three-bench core soil method for excavation. The research results can provide a theoretical reference for the construction of related tunnel projects.

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Section: Stress Release Ratementioning

confidence: 99%

Research on Excavation Method for Soft Rock Tunnel Based on Stress Release Rate

Nie,

He,

Kou

et al. 2024

Applied Sciences

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“…They found that the ratio of soil diameter had little effect on the support pressure when the working face was damaged, and the limiting support pressure had a linear relationship with the roadway diameter. Sun [19] studied the evolution mechanism of roadway face instability under different foundation conditions, and they defined three failure modes: front extrusion, front caving, and back caving. Lei [20] conducted a series of transparent clay model tests on the active stability of the shield face adjacent to the existing tunnel, based on the excavation process, failure mode, influence range, and support force.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Tunnel Face Support Pressure in Layered Soft Ground

Xiao,

Li,

Huang

2024

Applied Sciences

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In shield construction, the limit support pressure of the tunnel face has an important influence on ground settlement and construction safety. In this study, MIDAS GTS NX software was used to conduct a series of three-dimensional finite element simulations to investigate variations in excavation face support pressure under different layered ground conditions. By changing the shear strength parameters of the top or bottom layers, the influence of composite layers with different formation boundaries on the support pressure of the excavation face was studied. It was observed that when the formation boundary is placed above the axis, the support pressure of the excavation face is more sensitive to a change in the parameters in the lower part of the formation than in the upper part. Conversely, when the formation boundary lies below the axis, this sensitivity becomes reversed. Additionally, we derived a robust and accurate equation to estimate the limiting face support pressure in layered soft ground based on numerical modeling.

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“…Modeling test and field measurements are widely conducted to estimate tunneling-induced deformation, providing valuable engineering guidance for practical applications. [11][12][13][14][15][16][17]18,19 In many cases, the safety of existing structures should be evaluated before tunnel excavation to adjust the construction scheme, which is difficult to achieve through field measurements.…”

Section: Introductionmentioning

confidence: 99%

“…As an interesting topic in urban underground engineering, three types of approaches have been employed to study the soil–structure interaction: empirical approach, numerical approach, and analytical approach. Modeling test and field measurements are widely conducted to estimate tunneling‐induced deformation, providing valuable engineering guidance for practical applications 11‐17,18,19 . In many cases, the safety of existing structures should be evaluated before tunnel excavation to adjust the construction scheme, which is difficult to achieve through field measurements.…”

Section: Introductionmentioning

confidence: 99%

Approximate analytical solution of tunneling‐induced responses of a soil–foundation system using contact mechanics

Hong

Zhang

Zhou

et al. 2022

Num Anal Meth Geomechanics

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Estimating the tunneling‐induced responses of a soil–foundation system is crucial for safety control in urban underground engineering. In existing analytical research, the soil–foundation interaction is considered based on the Winkler soil model, with minimal focus on the continuum soil model. Hence, in this study, based on the continuum soil model, an approximate analytical solution is derived to predict the tunneling‐induced responses of a soil–foundation system considering the contact effect, where an approximation by replacing the surface of the complex variable solution for an elastic half‐plane with a tunnel with the mathematical expression of Sagaseta's ground loss settlement formula is adopted. A new strategy is proposed to optimize the derivation process, where the normal contact pressure after tunnel excavation is directly determined using the contact mechanics, and the proposed solution is obtained using the superposition principle. Subsequently, the approximation is proven to be accurate when the ratio of the buried depth to the tunnel radius is greater than 2.00. The proposed solution meets the given conditions and is in good agreement with numerical results, which verify the correctness of analytical solution. Furthermore, a parametric study is performed to investigate the influences of the key parameters on the mechanical responses. The results indicate that the proposed solution can quantitatively describe the nonlinear contact characteristics in the soil–foundation system; the contact effect is found to contribute to the discontinuous displacement and stress concentration when subjected to the significant effects of tunnel excavation.

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Model test and numerical analysis for the face failure mechanism of large cross-section tunnels under different ground conditions

Cited by 42 publications

References 46 publications

Research on Excavation Method for Soft Rock Tunnel Based on Stress Release Rate

Research on Excavation Method for Soft Rock Tunnel Based on Stress Release Rate

Numerical Simulation of Tunnel Face Support Pressure in Layered Soft Ground

Approximate analytical solution of tunneling‐induced responses of a soil–foundation system using contact mechanics

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