Resilience Assessment of Urban Water Distribution Networks under Disturbance Influence of Aftershocks

Water distribution networks (WDNs) are essential for urban water supply and postearthquake recovery. Conducting a seismic resilience assessment of a WDN and taking corresponding improvement measures can improve the disaster resistance capacity of the water system. A number of previous studies have evaluated the seismic resilience of WDNs, but seldom have taken into account the impact of aftershock disturbances. Aftershock disturbances may aggravate the damage to water distribution networks, prolong the repair time and reduce the recovery ability of WDNs. This study presents an improved framework for assessing WDN resilience considering aftershock disturbances. The stochastic principle and the elliptic ground vibration attenuation model were utilized to determine the spatial distribution of site ground vibration under the mainshock and aftershock. A superposition damage assumption was applied to incorporate aftershock effects in Monte Carlo simulations, and the pressure-driven analysis (PDA) and discrete-event simulation (DES) models were used to analyze the postearthquake hydraulic balance and model the restoration process. By constructing various scenarios, the probabilistic characteristic parameters of resilience indexes and the relationship between WDN resilience metrics and parameters related to aftershocks were investigated. A case study of a real WDN in China demonstrated that there is a correlation between aftershock-related parameters and resilience indexes. Moreover, relying solely on one resilience metric is insufficient for comprehensively understanding the seismic capacity of WDNs.