JOURNAL OF ROCK MECHANICS

JOURNAL OF ROCK MECHANICS

Three-dimensional modeling of stress arching and determination of zones with fracture potential in rock-fill dams in narrow valleys (case study: Lorestan Roodbar dam)

Document Type : Original Article

Authors
Amirhossein Amini 1
Ali Reza Kargar 1
Mohammad Hossein Khosravi 2
Hossein Behzadi 3
1 School of Mining Engineering, College of Engineering, University of Tehran, Tehran
2 Faculty of Mining Engineering, University of Birjand
3 Department of Mining Engineering, Isfahan University of Technology, Isfahan, Iran
10.22034/IRSRM.2025.504581.1018
Abstract
The existing statistics on the failure of embankment dams worldwide emphasize the importance of regular control over the behavior of such dams in order to assess the safety and stability of their different zones, both during the construction phase and during operation. The occurrence of arching and reduction in stress levels within the core of embankment dams is one of the factors that can lead to the initiation and development of cracks and pose a risk to the stability of the dam. In analysis of the state of stress distribution in embankment dams located in narrow valleys due to the three-dimensional effect (longitudinal and transverse) of stress arching within the core, two-dimensional models cannot obtain correct results, and this work is only possible with three-dimensional modeling. This research was conducted with the aim of determining the stress arching pattern within the clay core of embankment dams located in narrow valleys using a three-dimensional model and determining the zones prone to fracture according to the existing stress distribution, specifically, the data of the Lorestan Roodbar Dam was used and the mentioned objectives were determined precisely for this dam.
In this study, at first the three-dimensional modelling of the Lorestan Roodbar rock-fill dam, located in a narrow valley, was carried out using PLAXIS 3D V.22 software. Then, the intensity of arching phenomenon within the core was investigated at the end of construction and initial impounding stages. The maximum amount of arching was observed to occur at one fifth of the dam's height above the core base at the end of construction, and the intensity of arching increased after one year of dam impounding. In addition, the condition of the core in terms of tensile zones and, consequently, the potential for crack development and fracture at the end of construction was investigated. The dimensions of the expansion of these zones were determined, and indicated the presence of tensile zones in the upper elevations, around fifty meters from the crest, and near the abutments.
Keywords
Embankment dam with clay core
Arching
Numerical modelling
PLAXIS 3D
Subjects
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JOURNAL OF ROCK MECHANICS
Volume 8, Issue 4
Winter 2025
Pages 1-14