Experimental Study of Pressure and Soil Effects on Fluidization and Mobile Bed Zones around Buried Leaking Pipes
Milad Latifi, Shima Mohammadbeigi, Kambiz Farahi Moghadam, Seyed Taghi Omid Naeeni, Fouad Kilanehei
Abstract
Leakage in underground water pipes has become critical because of increasing water demand. Many studies have been conducted based on the knowledge of soil–water interaction, but few of them have investigated the internal erosion and possible zones forming around cracks as a result of leakage. This experimental investigation set out to achieve a better understanding of the mentioned problem. An unplasticized PVC pipe with a longitudinal crack was installed in a box with different types of soil, then water was flowed through the pipe. The aim was to determine the geometry of the zones possibly forming around the crack. The observation was made possible by installing the pipe beside a glass wall situated on the front face. Two zones (fluidization and mobile bed) with different directions that were geometrically different with soil types and water head pressures were observed. The effects of soil properties [e.g., median diameter (D50), Atterberg limits, porosity, and hydraulic conductivity] were also determined, and their relationships with the height, width, and maximum cross-sectional area of the mentioned zones were studied. The results demonstrated that the maximum height and maximum area of the zones were strongly correlated with water pressure.