Integrated System for Smart Installation, Renewal, and Management of Urban Underground Infrastructure — Structural Expansion Integrating Real-Time Subsurface Sensing × Digital Twin × Autonomous Robots × Circular Materialization × Citizen Consensus Formation —

This paper proposes an integrated system architecture to support the installation, renewal, and maintenance of urban underground infrastructure such as sewer pipelines. The framework combines real-time subsurface sensing, an integrated digital twin, planning optimization, autonomous robot swarms, trenchless underground fabrication, on-site material recycling, multi-layer risk monitoring with fail-safe mechanisms, and VR/AR-based citizen consensus support. By shifting from excavation-centered linear construction to dynamically synchronized parallel processes and circular material use, the system aims to reduce construction time, cost, environmental impact, and accident risk while minimizing disruption to urban functions and improving infrastructure resilience.