Soil-Pipeline interaction under localized soil Subsidence: Experimental Investigation

Localized soil subsidence can cause pipeline failures, yet relevant studies remain limited. This research uses 1 g scaling tests to explore granular soil behavior over a subsiding area with a crossing pipeline, employing Particle Image Velocimetry (PIV) and pressure sensors beneath trapdoors. Results reveal various failure mechanisms impacting load on pipelines, especially due to water-drop-shaped slip surfaces above the pipeline. The long side of the rectangular subsidence zone exhibited stronger load transfer compared to the short side. Neglecting the three-dimensional soil arching effect risks underestimating the pipeline load, particularly when the pipeline axis aligns with the long side of the subsidence. Greater distances between the subsidence zone and pipeline improve protection, though very close proximity can also be beneficial. The study suggests that inducing controlled soil failure above the pipeline may help reduce additional load, providing insights into mitigating pipeline damage from subsidence.