TUNNEL PORTAL INSTABILITY IN LANDSLIDE AREA AND REMEDIAL SOLUTION: A CASE STUDY

Authors

  • Farhad Farhadi Ayoublou Department of Civil Engineering, Amirkabir University of Technology, Tehran, Iran
  • Majid Taromi Department of Geotechnical Engineering, Islamic Azad University, Islamshahr Branch, Islamshahr, Iran
  • Abbas Eftekhari Department of Mining Engineering, Faculty of Engineering, Kashan University, Kashan, Iran

DOI:

https://doi.org/10.14311/AP.2019.59.0435

Keywords:

Slope instability, collapse, landslide, Sabzkuh Tunnel, remedial solution.

Abstract

The construction of tunnel portals in mountainous or slope areas often involves problems, which are closely related to factors, such as slope topography, geology, geotechnics, construction geometry and the tunnel excavation method. The activation of landslides or the acceleration of these events is one of the main challenges faced in the construction of tunnel portals. In this paper, we address the instability problem in Sabzkuh tunnel portal that has been excavated with a complex geological profile and high seismicity in Iran’s High Zagros region. The complexity and intense heterogeneity in geological formations, land acquisition problems and the lack of appropriate monitoring programs led to the instability of the tunnel portal. The excavation process started without applying appropriate techniques for a ground stabilization. The use of inappropriate tunnel excavation methods for this unstable geological structure resulted in an activation of an old Solaghan fault and several collapses in the tunnel. Crossing the collapsed areas and reinforcing the tunnel portal took about 7 months and imposed heavy costs on the project. This case study deals with the importance of the choice of the site location, ground and underground monitoring, analysing and summarizing the collected data in order to prepare a geological model before and during the construction process.

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Published

2019-11-01

Issue

Vol. 59 No. 5 (2019)

Section

Articles

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How to Cite

Farhadi Ayoublou, F., Taromi, M., & Eftekhari, A. (2019). TUNNEL PORTAL INSTABILITY IN LANDSLIDE AREA AND REMEDIAL SOLUTION: A CASE STUDY. Acta Polytechnica, 59(5), 435-447. https://doi.org/10.14311/AP.2019.59.0435