Keywords : embedded pipes
Evaluation the Effect of Pressure Head and Soil Type on Erosion and Subsidence of Soil Due to Defective Sewers
Kerbala Journal for Engineering Science,
Internal degradation induced in the metropolitan areas by leakage of sewers. As the resistance to erosion depends on the distribution of soil particles and the water pressure in sewer pipes, it is worthwhile to research the impact of water pressure on the soil erosion resistance of embedded pipes. This study aims to find physical model tests which simulating erosion and sinkhole development due to cyclic leakage in an experimental ground model through defect sewers. Proposed parameters like cyclic leaks through pipe crashes, eroded soil properties, initiation cavity, and evolution up until sinkhole failure were studied. During this process, the ground settlement monitored with Paricle:Image Velocimetry (PIV). Also, soils with various classification were utilized to identify the total subsidence for the different soil types. Five various water pressures were used:i.e., 0.8,1.1,1.4,1.7, and 2.0 meter,(7.85, 10.79, 13.73, 16.76, and 19.61 Kpa), respectively, and local sandy soil, local loamy soil, and local clayey soil also were used. The results showed that two parameters influence soil failure,noticebliy:- the first is water pressure which has a direct proportion to erosion and subsidence, where the increment of total eroded soil of 2.0 m water head reached 3.95 times 0.8 m head , and the second is soil types which showed that the clayey soil is highly sensitive and suffering more from subsidence rather than erosion on the contrary of other soil types.