Investigation of time-dependent effects on the convergence of circular tunnels

Document Type : Research Article

Authors

Dept. of Mining Engineering, Technical College, University of Tehran, Tehran, Iran

Abstract

Summary
A numerical solution based on the finite difference method is presented in this study which employs time-dependent parameters of surrounding rock mass of a circular tunnel. Applying the solution, the effect of time on induced stress and displacement is investigated. Moreover, the impact of support installation under time-dependent deformation of the surrounding mass is studied for various plastic behaviors.
Introduction
Nowadays, due to the development of urban areas, huge investments are made in creating infrastructures and their maintenance. Consequently, there is an increasing demand for the construction of underground structures such as tunnels. One of the most important issues in designing tunnels as an underground construction is its stability. On the contrary, the evaluation of induced stress and deformation fields is the most crucial matter after underground excavation. This excavation could change the initial stress components and produce an induced stress field causing further displacements around the underground structure. This evolution in stress and deformation regime may not occur instantly, instead it might develop over long periods of time. A ground reaction curve is a beneficial approach to describe these deformations based on the convergence-confinement method. For simplicity, it is assumed in this method that rock mass mechanical properties are isotopic, and in situ hydrostatic stress field exists making the problem as an axisymmetric problem. In the majority of the analytical solutions for the ground reaction curve, the rock mass constitutive model is assumed as elastic perfectly plastic and elastic brittle plastic which simplifies the solving process. Moreover, in some other solutions, strain softening constitutive model is implemented. Nonetheless, considering all this research, the actual rock mass behavior which is affected by time is neglected...

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References

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History

  • Receive Date: 09 December 2022
  • Revise Date: 28 February 2023
  • Accept Date: 28 February 2023

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