Constitutive Models and Determining Methods Effects on Application of Convergence–Confinement Method in Underground Excavation

Mousivand, Mohsen; Maleki, Mohammad

doi:10.1007/s10706-017-0426-2

Cited by 11 publications

(4 citation statements)

References 29 publications

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“…This study attempts to clarify the deformation evolution law of tunnel surrounding rock from the perspective of stress release. However, the concept of stress release is based on many assumptions [22][23][24][25][26], and there are difficulties in monitoring the stress release process. Therefore, it is a feasible research method to invert the stress release law by the deformation of the surrounding rock.…”

Section: Discussionmentioning

confidence: 99%

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Design of Tunnel Initial Support in Silty Clay Stratum Based on the Convergence-Confinement Method

Liu

Zhao

et al. 2023

Sustainability

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The stress release ratio of the surrounding rock in tunnel excavation is one of the most important indicators that affect the stress distribution and displacement of the surrounding rock. To determine the variation law of the stress release ratio of the surrounding rock during excavation in silty clay stratum, the stress release law is determined based on the convergence–confinement method (CCM) and field test data. The stress release law of the surrounding rock under support is determined based on the displacement back analysis method. The permitted displacement safety factor of silty clay under different subgrade conditions and the optimal supporting time of the initial supporting structure are determined by comparing the stress release ratio with surrounding rock displacement. The results indicated that the stress release ratio of surrounding rock in the silty clay stratum is approximately 78–90% when the coordinate displacement of the supporting structure and surrounding rock is stable under the current excavation and support conditions. For the surrounding rock of subgrade V in the silty clay stratum, the safety factor of the permitted displacement in the tunnel vault is approximately 2.91, and the initial support should be carried out within 1 m behind the face advancing. For the surrounding rock of subgrade VI1, the safety factor of the permitted displacement is 1.40, and the initial support must be carried out 1 m ahead of the tunnel face. For the surrounding rock of grade VI2, the initial support must be carried out 4 m ahead of the tunnel face.

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Section: Discussionmentioning

confidence: 99%

“…To study the stress release of the surrounding rock and the stress characteristics of the supporting structure [22] during tunnel excavation, numerical calculations [23][24][25][26] and field tests [27,28] are commonly used, and the numerical calculation model must be revised by the data of field tests before it has reference value.…”

Section: Introductionmentioning

confidence: 99%

Design of Tunnel Initial Support in Silty Clay Stratum Based on the Convergence-Confinement Method

Liu

Zhao

et al. 2023

Sustainability

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“…To distinguish whether the stress at the points C and E are in the elastic or the plastic regions, this study presents two analysis situations that include that stress state of As shown in the upper part of Figure 1, the third curve of this method is called the longitudinal displacement profile (LDP) [11] or the confinement loss curve (CLC) [2][3][4]. Recent studies have shown some divergent views on the assumptions and definitions of confinement loss in the CCM analysis [29][30][31][32][33]. This principle suggests that the confinement loss increases while the radial stress decreases during the advancing excavation of the tunnel face and uses the concept of increment to simulate this effect, and its value is between 0 and 1 [3,34,35].…”

Section: Equations Derivation Of the Direct Calculation Methods (Dcm)mentioning

confidence: 99%

Verification and Comparison of Direct Calculation Method for the Analysis of Support–Ground Interaction of a Circular Tunnel Excavation

et al. 2022

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A direct algorithmic process can deal with the solution of the support–ground interaction in a circular tunnel excavation through the convergence-confinement method (CCM) with the concept of increment. This process is the so-called direct calculation method (DCM) that can find solutions, the mobilized support pressure and the convergence, in the analysis of CCM. To achieve the solution, using two linear equations in the elastic region and Newton’s recursive method to find the roots in the plastic region are proposed and realized by a calculated spreadsheet. The validity of the algorithmic process for the analytical solutions was investigated and verified by the finite element computation, and compared with the published results, Rocksupport (2004), Oreste (2009), and Gschwandtner-Galler (2012). The results obtained between DCM and related studies show no significant differences.

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“…This CLC principle shows that during the continuous advancement of the tunnel face, the confinement loss increases, resulting in a decrease in the radial stress around the tunnel and an increase in the radial displacement. Recently, much research literature has mentioned the effect of confinement losses around tunnels and constitutive models using numerical procedures to improve the accuracy of CCM analysis [24][25][26][27][28]. By implementing the convergence-confinement method, engineers can effectively manage the convergence behavior of rock masses in tunneling projects.…”

Section: Introductionmentioning

confidence: 99%

An Improved Incremental Procedure for the Ground Reaction Based on Hoek-Brown Failure Criterion in the Tunnel Convergence-Confinement Method

Lee

2023

Mathematics

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The purpose of this study is to introduce the Hoek–Brown nonlinear failure criterion into the convergence–confinement method (CCM), which is based on the linear failure criterion, and implant it into the ground reaction curve (GRC) in this theory. Based on consistent and rigorous theoretical analysis and according to the mechanical relationships, the principle of equilibrium, the material constitutive law, and the strain/displacement compatibility equation are used to deduce the closed-form analytical solution of the stress/displacement of the rock mass in the plastic region and to complete the simulation and interpretation of the nonlinear behavior of surrounding rock due to the advancing excavation of a circular tunnel. In this paper, confinement loss is regarded as the concept of increment in numerical analysis, and the calculation process and analysis steps of the explicit analysis method (EAM) are proposed. This method can not only realize the calculation of analytical solutions but can also be performed using simple spreadsheets. In addition, to verify the feasibility of this calculation method, this study uses published data to verify the validity of the analytical solution implemented by the incremental procedure and to study the influence of nonlinear failure criteria on the GRC, especially the mechanical behavior at the intrados of the tunnel and the distributions of tress/displacement on the cross-section of the tunnel. A comparison between the published results and the proposed solution in this study reveals consistent and favorable trends.

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Constitutive Models and Determining Methods Effects on Application of Convergence–Confinement Method in Underground Excavation

Cited by 11 publications

References 29 publications

Design of Tunnel Initial Support in Silty Clay Stratum Based on the Convergence-Confinement Method

Design of Tunnel Initial Support in Silty Clay Stratum Based on the Convergence-Confinement Method

Verification and Comparison of Direct Calculation Method for the Analysis of Support–Ground Interaction of a Circular Tunnel Excavation

An Improved Incremental Procedure for the Ground Reaction Based on Hoek-Brown Failure Criterion in the Tunnel Convergence-Confinement Method

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