Numerical study on the effect of intersection angle and loading magnitude on leakage-induced ground collapse

Abstract

Ground collapse is one of the most common urban disasters, with pipeline leakage being a significant cause. Pipelines are regarded either parallel or perpendicular to the road, using a single variable to control the soil strength or the cavity shape, which over-simplified the development of soil cavities. In this paper, with a coupled method of element deactivation and strength reduction, a more realistic 3D finite element model was established to simulate the development of soil cavities caused by pipeline leakage. Effects of burial depths, intersection angles between loading areas and pipelines, and loading magnitudes on the process of road collapse were explored. The results showed that: (1) an increase in load could alter the collapse mode, with plastic zones appearing at the edges of the soil cavity, leading to a larger collapse impact range; (2) the orientation of the loading area significantly influenced the rate of surface subsidence post-collapse and the range of collapse impacts; (3) using the strength reduction method, a factor of collapse risk was defined to access the collapse risk under pipeline leakage. Based on the computational results, stability charts and collapse risk charts were proposed, providing a theoretical foundation for the prevention and control of urban traffic disasters.