Dynamic resilience assessment and emergency strategy optimization of natural gas compartments in utility tunnels

Abstract

As a kind of critical infrastructure of energy transportation, so-called ‘utility tunnels’ have been developed around the world. Hosting a natural gas pipeline inside the natural gas compartment of a utility tunnel facilitates its maintenance but also brings potential explosion concerns due to the confined space. Although some work focuses on the risk analysis of the natural gas pipeline inside utility tunnels, a resilience assessment is needed for dynamically modeling leakage with interacting safety barriers. In this paper, a resilience assessment model of the natural gas compartment of utility tunnels is elaborated based on numerical simulation considering interacting barrier modeling, including sensors, a ventilation system, and the possibility of emergency shutdown. Based on the calculated (natural gas compartment) resilience for casualty and economic loss, ventilation strategies and sensor layouts can be recommended and optimization is possible. Meanwhile, the delay effect of safety barriers is investigated in this work, and the unequal interval layouts of sensors are explored and proven to be effective without any further cost. The proposed resilience assessment model can be important to further improve the safety management of utility tunnels and other confined spaces where hazardous gases are transported.