The Influence of Small-Hole Leakage in Buried Gasoil Pipelines on Soil Structure under Different Leakage Velocities

Abstract

To investigate the impact of small-hole leakage in the buried gasoil pipeline on soil, a numerical model is established based on the CFD-DEM coupling method. The effect of spilled oil on soil morphology and structure is revealed. It indicates that three zones with increased porosity of soil under the small leakage hole are formed: the cavity zone, the fluidized zone, and the shear dilation zone. The effect of spilled oil at different leakage velocities on soil is studied and the morphological and structural changes in the soil are quantitatively analyzed. The results show that when the leakage velocity ν ⩽ 20 m/s, the areas of the cavity and fluidized zone gradually increase over time with the decreasing rate. When ν > 20 m/s, the areas of them initially increase and then decrease over time. The area of the shear dilation zone gradually increases under varying velocities, with the decreasing rate until it stabilizes. The depth and width of all zones gradually increase over time, with the decreasing rate until it is nearly unchanging. Additionally, the depth tends to decrease under higher velocities. The velocity has minimal impact on the width of the cavity and fluidized zones but shows a negative correlation with the width of the shear dilation zone. The morphological and structural changes in soil caused by small-hole leakage in buried gasoline pipelines is revealed in this study, and it can provide a theoretical basis for subsequent research on oil spill migration.