Paper contribution

Experimental investigation of undercut stratified rocks using base friction technique

Mohammad Hossein Khosravi; Amir Kheirabadi; Alireza Kargar; Gholamreza Saedi

Proceedings
EUROCK 2026
Pages
1089-1094
Submitted
12 May 2026
Accepted
15 June 2026
Published
12 August 2026

Summary

Abstract

One of the most important factors affecting the stability of the tunnel as well as the shape of the collapsed area above the tunnel is the angle of the layers. In this study, the distribution of failure at the top of the tunnel in stratified rock mass has been investigated. In order to investigate collapsed area above the tunnel, physical modeling has been conducted. In this research, two variables have been considered to study the stratified rock mass: the span size and the angle of the layers. The span of the tunnel are 200, 250, 300, 350 and 400 mm. Angles of 0, 30, 45, 60. Also, the height of the tunnel in all tests is constant and equal to 80 mm and the excavated tunnel is rectangular. The dimensions of the whole test environment are 600 * 600 mm. Also, the model is restrained at the lower, left and right borders and has no movement and only the upper border of the model is free. Due to these conditions, a total of 20 experiments were performed. The results of this study show that, at angles of 30, 45 and 60 degrees, the shape of the collapsed area at the top of the tunnel is similar to a right triangle and equilateral triangle, respectively. Also, increasing the span of the tunnel does not affect the shape of the collapsed area and only the area of the collapsed area increases and the amount of this increase is linearly related to span of the tunnel. Also, the 30 degree angle has the lowest and the horizontal mode has the most collapsed area at the top of the tunnel.

Contributors

Authors

  1. Mohammad Hossein Khosravi Department of Mining Engineering, Faculty of Engineering, University of Birjand, Birjand, Iran ORCID 0000-0002-7600-5786
  2. Amir Kheirabadi School of Mining Engineering, College of Engineering, University of Tehran, Tehran, Iran
  3. Alireza Kargar School of Mining Engineering, College of Engineering, University of Tehran, Tehran, Iran
  4. Gholamreza Saedi Millennium Iranian Construction and Trading Company, Tehran, Iran

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References

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