Designing a support system and conducting stability analysis for the branching lower headrace tunnels at the Rudbar Pumped Storage Power Plant Project site

Heidari, Masoud; Jowkar, Mohammad Hossein; Khamehchiyan, Mashalah; Sharifi Boroujerdi, Mohsen

doi:10.22071/gsj.2026.537222.2213

Designing a support system and conducting stability analysis for the branching lower headrace tunnels at the Rudbar Pumped Storage Power Plant Project site

Articles in Press

Document Type : Original Research Paper

Authors

Masoud heidari ¹

Mohammad Hossein Jowkar ¹

Mashalah Khamehchiyan ²

Mohsen Sharifi Boroujerdi ³

¹ Engineering geology Department, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Iran

² Tarbiat Modares University, Faculty of Basic Sciences

³ Mahab Ghods Consulting Company

10.22071/gsj.2026.537222.2213

Abstract

Pumped storage power plants provide a means of generating and storing electricity during peak demand periods. Given the importance of these facilities and the understanding that many underground infrastructure issues arise after construction and neglect of certain design flaws, thus conducted a study to evaluate the structural stability of the branching lower headrace tunnels at the Rudbar Pumped Storage Power Plant in Lorestan, utilizing a combination of empirical classification techniques (Q, RMR, RMi, GSI, and Protodiakonov coefficient) and numerical modeling (FLAC3D software). The results obtained show that the underground space is stable with a low safety factor. Therefore, it is necessary to install a maintenance system. Following the installation of the support system, the internal forces were calculated and the system's safety factor was assessed using capacity diagram and Sakurai hazard level. The analysis revealed that by applying 10 centimeters of shotcrete and steel grid network with totally injected anchors with 2*2 grid and length of two meters, a safety factor of 1.5 can be attained. In addition, the rock mass surrounding the tunnel, as indicated by the ground response curve and longitudinal deformation profile, displays elastoplastic behavior, and excavation step 2 meters (full section) was obtained for the excavation.

Keywords

Tunnel Branch

Support system

Rudbar Lorestan

Capacity Diagram

FLAC 3D

Subjects