Mechanism of Pipeline-Induced Road Collapse under Low Groundwater Levels: Insights from Erosion Dynamics and Engineering Implications

Urban road collapses cause substantial economic losses and social disruption while directly compromising the integrity of underlying pipeline networks. Despite extensive research on failures stemming from underground water seepage following pipeline damage, the collapse mechanisms triggered when groundwater levels fall below the pipeline burial depth remain insufficiently understood. This study employs a combined approach of laboratory model experiments and software simulations to systematically investigate water flow–induced soil erosion and its impact on road collapse following pipeline damage. The results demonstrated that under low-groundwater conditions, the extent of erosion into the pipeline correlates positively with soil permeability. Moreover, the formation and lateral expansion of cavities—observed even at small scales—indicate an urgent need to extend monitoring zones and implement reinforcement strategies over wider areas. In scenarios with low soil permeability, vortex formation inside pipelines leads to elevated wall pressures, further underscoring the importance of proactive surveillance of adjacent pipeline segments, particularly during periods of reduced water supply. These findings not only advance the theoretical understanding of erosion mechanisms but also provide a rigorous foundation for developing risk-based maintenance and preemptive measures to enhance pipeline system integrity.