Risk-Based Decision Making Method for Selecting Slope Stabilization System in an Abandoned Open-Pit Mine

Mahnoush Gharehdaghi,Hesam S Tehrani,Ali Fakher

doi:10.2174/1874836802014010198

Mahnoush Gharehdaghi, Hesam S Tehrani + Show 1 more

Open Access

https://doi.org/10.2174/1874836802014010198

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Abstract

Background:The construction and stabilization of deep excavations are associated with several uncertainties due to heterogeneous geological conditions. Therefore, the conventional methods of slope stability analysis do not provide reasonable results.Aim:Hence, it is logical to perform reliability analysis and also risk assessment to make a wiser decision under uncertainty for choosing the proper stabilization method of slopes.Methods:In this regard, a real case study, a 50-meter-deep abandoned open-pit mine, is considered. In the past, the studied deep excavation was located in a rural area, away from the important structures. However, due to the development of the city, the open-pit mine is now located in the city. Furthermore, the Kan River is located on the eastern side of the excavation. Deterministic analysis showed that that Factor of Safety is not sufficient for permanent condition; thus, the deep excavation may have destructive impacts on the adjacent structures and infrastructures by putting them in danger in the case of failure.Results:These circumstances resulted in using reliability analysis and risk assessment using non-deterministic approach. Random Set Finite Element Method (RS-FEM), a non-probabilistic method, is used in determining how much the slope is reliable. The upper and lower bounds of probability of excessive displacement and probability of failure are obtained using RS-FEM by Plaxis2D software. Afterward, HAZUS is successfully used to quantify the economic risk of different stabilization alternatives by defining various scenarios in order to consider the consequences of excavation failure on adjacent utilities and infrastructures.Conclusion:The best alternative is defined as the stabilization method with the lowest economic risk. As a result, it is noticeable that this paper provides a comprehensive methodology for decision making, based on reliability analysis and risk assessment, in stabilizing slopes.

Highlights

Nowadays, the rate of underground construction, such as deep excavation and tunneling, has increased
It is noticeable that this paper provides a comprehensive methodology for decision making, based on reliability analysis and risk assessment, in stabilizing slopes
In the case of probability of failure, the Berm Stabilization Method (BSM) has the lowest value in Table 16 as well

Summary

Introduction

The rate of underground construction, such as deep excavation and tunneling, has increased. Deep and wide pits are abandoned after the collection of sand and gravel [4]. Such activity leads to detrimental effects on the ecosystem, and it may put the health of people in danger due to the possible instability of the deep excavation. The improvement of the excavated area is necessary to prevent the negative impacts of pits of sand and gravel, which are abandoned after used. One of the crucial activities in this regard is stabilizing the slopes of the deep excavation to make sure it would not threaten the surrounding area. The conventional methods of slope stability analysis do not provide reasonable results

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