Influence of Geogrid Reinforcement on Pipeline Failure Mechanisms under Full Pipe Flow: Insights from Transparent Soil Modelling

The mechanisms governing underground pipeline rupture in erodible soils remain a critical focus in geotechnical engineering, particularly under full pipe flow conditions. In this study, the impact of geogrid reinforcement on the fracture behavior of buried pipelines was systematically investigated using transparent soil modelling techniques, which enabled real-time visualization of subsurface erosion dynamics. Geogrid reinforcement was applied across varying spatial extents to identify the optimal reinforcement zone for mitigating collapse-induced failure. Soil-particle migration and cavity formation were monitored under different hydraulic scenarios, facilitating a detailed characterization of erosion pit evolution and subgrade instability. Test results demonstrated that appropriately positioned geogrid reinforcement significantly delayed the initiation and progression of subsidence, reduced the depth and volume of collapse zones, and enhanced the structural integrity of the surrounding subgrade. Under pressure-free conditions, geogrid installation was found to slow the erosion rate, whereas under full pipe flow, the reinforcement effectively suppressed sudden cavity collapse and curtailed the expansion of erosion-prone areas. These findings highlight the critical role of geogrid placement in maintaining pipeline stability by moderating soil loss and controlling void development. The use of transparent soil provided unique insights into the spatial and temporal characteristics of internal erosion, allowing for a more precise delineation of geogrid influence zones. This research contributes to a deeper understanding of subsurface failure mechanisms in reinforced systems and offers practical guidance for infrastructure resilience against hydraulic-induced ground deformation.