A Novel Framework for Enhancing Resilience of Urban Underground Drainage Networks in IoT Sponge City

Amid increasing extreme rainfall events, urban pluvial flooding poses a significant threat to city infrastructure and public safety. To address the limitations such as poor coordination between subsystems and low resilience of conventional IoT frameworks in underground drainage networks, this paper proposes a resilience-driven architecture termed R⁴-UDN. The framework integrates four signature mechanisms: event-triggered sensing, resimulation-in-loop， cascade-aware control, and cross-layer KPI alignment, forming a closed-loop management system. The paper introduces a multi-stage resilience index and embeds it into a semi-Markov cascade model to capture system performance dynamically. Furthermore, it optimizes the resilience and sequence-sensitive cost. A case from Chengdu, China, is studied to confirm that the proposed method significantly enhances resilience compared to conventional strategies, validating the practical value of R⁴-UDN for enhancing the resilience of sponge city underground drainage systems.