🤖 AI Summary
To address the multi-objective optimization challenge—balancing cost, safety, and service continuity—in urban infrastructure maintenance, this paper proposes a utility-driven deep multi-objective reinforcement learning (MORL) framework. Methodologically, it innovatively integrates utility theory into MORL by designing a Pareto-aware reward shaping mechanism and a hierarchical policy decomposition architecture; further, it employs graph neural networks for topology-aware state representation and combines Pareto-frontier guidance with Monte Carlo policy evaluation. Evaluated on benchmark simulations of bridge and water distribution networks, the framework reduces lifecycle maintenance costs by 18.7%, improves system reliability by 9.3%, and yields decision policies validated by engineering practice. Its transparent, interpretable policy logic significantly enhances practical applicability and domain adoption.