The Effect of GSI and mi on the Stability of 3D Twin Tunnel in Limestone

Authors

  • Jalal Zenah
    Affiliation
    Department of Engineering Geology and Geotechnics, Faculty of Civil Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
  • Péter Görög
    Affiliation
    Department of Engineering Geology and Geotechnics, Faculty of Civil Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
https://doi.org/10.3311/PPci.22239

Abstract

The Generalised Hoek-Brown (GHB) failure criterion is one of the most used criteria to study the behaviour of the rocks; affected parameters of the Hoek-Brown equation are Geological Strength Index (GSI), intact rock constant (mi), and Disturbance factor (D). GSI is one of the rock classification systems used to evaluate jointed rocks. In light of this equation, this paper studies the stability of unsupported twin tunnels in a weak rock by changing the mentioned parameters (GSI, mi) to find the relation between the stability and these parameters under different distances between the centres of the tunnels (L). The tunnels have a circular cross-section with a diameter (B), and they have been modelled in three dimensions using Rocscience software package (RS3). The results showed that the stability of the tunnels, which was represented by the strength reduction factor (SRF), increased as a result of increasing L/B or GSI in the studied range; for mi, the modelling results showed that the SRF value increased while mi value was increased.

Keywords:

GSI, mi, GHB, stability analysis, RS3, twin tunnel, tunnels distance, soft rock

Citation data from Crossref and Scopus

Published Online

2024-02-14

How to Cite

Zenah, J., Görög, P. “The Effect of GSI and mi on the Stability of 3D Twin Tunnel in Limestone”, Periodica Polytechnica Civil Engineering, 68(2), pp. 600–607, 2024. https://doi.org/10.3311/PPci.22239

Issue

Section

Research Article