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Limits of the Convergence-Confinement method for deep tunnels in weak rock masses: Comparison with axisymmetric modelling

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Bibliographic Details
Title: Limits of the Convergence-Confinement method for deep tunnels in weak rock masses: Comparison with axisymmetric modelling
Authors: Fenneteau, B., Deck, O., Mehdizadeh, Rasool, Laigle, F.
Contributors: Fenneteau, Baptiste
Source: Tunnelling into a Sustainable Future – Methods and Technologies ISBN: 9781003559047
Publisher Information: Informa UK Limited, 2025.
Publication Year: 2025
Subject Terms: [SPI.GCIV.GEOTECH] Engineering Sciences [physics]/Civil Engineering/Géotechnique, [SPI.GCIV] Engineering Sciences [physics]/Civil Engineering
Description: This paper investigates the shortcomings of the convergence-confinement method, when used for deep tunnels in weak rock masses. Axisymmetric numerical calculations are performed to evaluate the ground pressure on supports as a function of the distance to the face, the stiffness of the support and the mechanical properties of the ground. A comparison with the traditional convergence-confinement method (CV-CF) is provided to demonstrate the underestimation of the ground pressure on the support calculated with the CV-CF method. However, this shortcoming is not clearly identified when the CV-CF method is used at the preliminary design stages of projects. This paper investigates the assumption that these discrepancies for classical tunnelling situations are compensated by the use of safety factors, which are typically applied alongside the CV-CF method. The obtained results show that the safety factors compensate the discrepancies only for classical tunneling situations with small radial deformation.
Document Type: Part of book or chapter of book
Conference object
File Description: application/pdf
Language: English
DOI: 10.1201/9781003559047-271
Access URL: https://hal.science/hal-05185317v1/document
https://doi.org/10.1201/9781003559047-271
https://hal.science/hal-05185317v1
Rights: CC BY NC ND
Accession Number: edsair.doi.dedup.....45a973174ba2401df42c6b44d0d23b64
Database: OpenAIRE
Description
Abstract:This paper investigates the shortcomings of the convergence-confinement method, when used for deep tunnels in weak rock masses. Axisymmetric numerical calculations are performed to evaluate the ground pressure on supports as a function of the distance to the face, the stiffness of the support and the mechanical properties of the ground. A comparison with the traditional convergence-confinement method (CV-CF) is provided to demonstrate the underestimation of the ground pressure on the support calculated with the CV-CF method. However, this shortcoming is not clearly identified when the CV-CF method is used at the preliminary design stages of projects. This paper investigates the assumption that these discrepancies for classical tunnelling situations are compensated by the use of safety factors, which are typically applied alongside the CV-CF method. The obtained results show that the safety factors compensate the discrepancies only for classical tunneling situations with small radial deformation.
DOI:10.1201/9781003559047-271