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Shallow tunnel face stability analysis using finite elements

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Category: Content №1 2021

Last Updated on 05 March 2021

Published on 30 November -0001

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Authors:

I.Kahoul, Badji Mokhtar University, Annaba, Algeria, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

S.Yahyaoui, National Polytechnic School, Algiers, Algeria

Y.Mehidi, Larbi Tebessi University, Tebessa, Algeria

Y.Khadri, Badji Mokhtar University, Annaba, Algeria, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

повний текст / full article

Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu. 2021, (1): 091 - 097

https://doi.org/10.33271/nvngu/2021-1/091

Abstract:

Purpose. This work aims to study the tunnel face stability (Algiers subway Tunnel) and evaluate common numerical procedures that are used for analyzing the tunnel face stability. Two-dimensional (2D) and three-dimensional (3D) Finite Element (FE) modeling using PLAXIS programs.

Methodology. Tunneling is executed by the NATM method; two types of calculations are used. The first one is done by reducing the applied face pressure until the face is collapsed. The second calculation method involves the Phi-c (the angle of internal friction and bonding) reduction method, which is based on calculating the safety factor of the shear strength of the soil. Both methods are applied for 2D and 3D FE-modelling.

Findings. It is found that determining the applied face pressure is an important consideration to avoid face failure or excessive deformations with numerical methods resulting in more precise findings than analytical methods.

Originality. The originality of this work is the use of both 2D and 3D modelling, combined with two approaches: structural analysis of plastic state and Phi-c reduction method based on calculating the safety factor of the shear strength of the soil.

Practical value. This study illustrates that the reducing shear strength method is much better than the reducing applied face pressure method. Moreover, the result of 3D FE-modelling gives a better prediction comparing with the 2D FE-modelling results.

Keywords: tunnel, numerical modelling, tunnel face stability, Plaxis 2D, Plaxis 3D tunnel, Algiers subway tunnel

References.

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