ارزیابی ریسک فرایند تونلکاری با استفاده از روش تجزیه و تحلیل حالات شکست و اثرات آن

Title

Risk Assessment of a Tunnelling Process Using Machinery Failure Mode and Effects Analysis (MFMEA)

English Abstract

Abstract In recent years, risk management associated with safety and reliability of the process especially in oil and gas industry has been widely used. For this purpose, different methods of risk analysis have been developed and successfully applied. Greater levels of complexity in tunnelling using TBM (Tunnel Boring Machine) especially in gassy tunnels with a large volume of water coming out of them, allow higher chances of failure that may increase the potential for tunnelling facilities to become more hazardous. When there is an ever increasing awareness of hazardous risks that need to be managed by the industrial community, the risks need to be analyzed. This paper presents the results of a study on risk management in a tunnel excavation with TBM. MFMEA was applied to analyze the risks of a tunnelling process. In order to apply MFMEA, 7 main systems and components involved in a tunnelling process were selected and split into subsystems. In total, 71 failure modes were then postulated for all subsystems. In the next step, the effects of every failure of each subsystem were listed. Safeguards or controls that might prevent or mitigate the effects of each failure were then listed. In the final step, essential 1 remedial actions to prevent or mitigate the failure were recommended. Risk Matrix was developed for each possible failure to be used for risk ranking. For this purpose the Risk Priority Number (RPN) was estimated for each failure mode to identify the most critical failures. The results revealed that, the failure of the ventilation system (RPN=480) is the most critical failure. The TBM failure due to bad rock condition (RPN=240) and rolling stock failure due to unleveled rails (RPN= 200) are the next significant critical failures. The findings from this study were applied to a long tunnel under construction and significantly reduced the accidents during the tunnelling period. Tracking of the accidents occurred during the next 2 years showed that MFMEA is a perfect method for risk management in tunnelling process as well. Key Words: Hazards Identification; Risk Analysis; Risk Management, Tunnelling.

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