Risk and Reliability Based Calibration of Design Codes for Submerged Floating Tunnels

Baravalle, Michele; Köhler, Jochen

doi:10.1016/j.proeng.2016.11.547

Cited by 11 publications

(15 citation statements)

References 0 publications

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“…The ranges of the reliability indices of the support (for each rock domain) fall within 0.6 and 3.25. In comparison with existing research, these results are within the common range of the reliability index of geotechnical structures (Baravalle and Köhler 2016;Goh and Zhang 2012;Müller 2010;Skrzypczak et al 2017). The next question is to determine the level of reliability acceptable of each support.…”

Section: Discussionsupporting

confidence: 59%

Reliability Analysis of Rock Supports in Underground Mine Drifts: A Case Study

Adoko

Yakubov

Kaunda

2021

Preprint

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Support failures in mine drifts represent potential hazards threatening underground mine safety and productivity. The aim of this study is to determine the reliability index associated with the rock supporting elements used in Ridder-Sokolny mine, an underground mine located in East Kazakhstan. Numerical simulations of the drift support and the first order reliability method (FORM) were employed to carry out the analysis. Several support cases were considered including; shotcrete, bolting, concrete, and combined bolting and concrete as well as unsupported drift case. For each support case, the factors of safety (FS), the reliability index (β) and the probability of failure (PF) were determined in accordance with the corresponding rock mass quality and excavation geometry. The results indicated the average FSs varied little for the different support cases (except for shotcrete); while β and PF vary more significantly between 0.62–3.25 and 0.05–27 (×103 %) factor depending on the rock conditions and support installed. The probability of failure of the rock support increases with a decrease in the rock mass quality. Similar trends were observed with an increase of the width/height ratio of the excavations for the same rock domain. These results illustrated that a single FS value obtained from a deterministic method may not always provide a sufficient indication of safety. This is in agreement with the field observations (many of the supports failed). Hence, on the basis of the reliability index of the supports, the requirement in terms of coefficient of variability of the rock mass quality to meet the target performance level was proposed. It is concluded that the results of this study could help improving the drift support design in Ridder-Sokolny mine.

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Section: Discussionsupporting

confidence: 59%

Reliability Analysis of Rock Supports in Underground Mine Drifts: A Case Study

Adoko

Yakubov

Kaunda

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…3.25. In comparison with existing research, these results are within the common range of the reliability index of geotechnical structures(Baravalle and Köhler 2016;Goh and Zhang 2012;Müller 2010;Skrzypczak et al 2017). The next question is to determine the level of reliability acceptable of each support.…”

supporting

confidence: 59%

“…Based on Table 7 and Table 9 it can be suggested that β>3.0 correspond to high performance; β ranging between 2 and 3, good performance; and β below 2.0, poor performance reliability level. Further study could aim to determine the acceptable reliability level perhaps using a riskbased method, where the consequences and level of failure should be assessed thoroughly as suggested by recent research (Baravalle and Köhler 2016). This approach could be useful for drift support design since the consequences and hazards of support failure can be established and considered explicitly in a calibration.…”

Section: Discussionmentioning

confidence: 99%

Reliability Analysis of Rock Supports in Underground Mine Drifts: A Case Study

2021

View full text Add to dashboard Cite

Support failures in mine drifts represent potential hazards threatening underground mine safety and productivity. The aim of this study is to determine the reliability index associated with the rock supporting elements used in Ridder-Sokolny mine, an underground mine located in East Kazakhstan. Numerical simulations of the drift support and the first order reliability method (FORM) were employed to carry out the analysis. Several support cases were considered including; shotcrete, bolting, concrete, and combined bolting and concrete as well as unsupported drift case. For each support case, the factors of safety (FS), the reliability index (β) and the probability of failure (PF) were determined in accordance with the corresponding rock mass quality and excavation geometry. The results indicated the average FSs varied little for the different support cases (except for shotcrete); while β and PF vary more significantly between 0.62-3.25 and 0.05-27 (×10 3 %) factor depending on the rock conditions and support installed. The probability of failure of the rock support increases with a decrease in the rock mass quality. Similar trends were observed with an increase of the width/height ratio of the excavations for the same rock domain. These results illustrated that a single FS value obtained from a deterministic method may not always provide a sufficient indication of safety. This is in agreement with the field observations (many of the supports failed). Hence, on the basis of the reliability index of the supports, the requirement in terms of coefficient of variability of the rock mass quality to meet the target performance level was proposed. It is concluded that the results of this study could help improving the drift support design in Ridder-Sokolny mine.

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“…SFT structures have not been built yet and the discussion about the required target reliability for SFT is ongoing. Both [15,16] contribute to this discussion. This paper presents a design adaption related to uncertainty and less predictable loading over time that is independent to the required target reliability.…”

Section: Introductionmentioning

confidence: 91%