Dynamic risk assessment model for third-party damage to buried gas pipelines in urban location class upgrading areas

Abstract

Buried gas pipeline leakage accidents caused by third-party interference in urban location class upgrading areas are time-varying and can cause serious consequences. This study proposed an integrated dynamic risk assessment model to address this issue. First, a bow-tie model combining a fault tree (FT) with an event tree (ET) was used to construct an overall evolutionary process from basic events to accidents and thus mapped into a Bayesian network (BN). The prior probabilities of basic events in FT and safety barriers in ET were determined by four types of methods, and the critical basic events were identified by sensitivity analysis. By integrating the Hierarchical Bayesian analysis method with time-varying precursor data, the dynamic probability updating of critical basic events and safety barriers was achieved, enabling adaptation of accident probabilities using BN. Then, a dynamic calculation method for accident consequences was proposed by integrating the appropriate leakage rates with a new time-varying method for calculating fatalities. Finally, a new risk matrix method was proposed to dynamically evaluate the risk level by integrating the accident probabilities with the consequences. A case study showed that the proposed model could dynamically evaluate the integrated accident risk, providing explicitly quantified support for risk management and emergency rescue of buried gas pipeline networks in urban location class upgrading areas.