Soil and Groundwater Erosion Rates into a Sewer Pipe Crack

As sewer pipes age, groundwater and the surrounding soil can enter into the sewer system through various defects on the pipe wall. Groundwater infiltration and soil erosion through cracked sewer pipes can result in increased sewage loading and cause sinkhole problems. A reliable model is needed to assess the soil and water erosion rates. By incorporating the related resistances during the erosion process, this paper presents improved expressions for calculating soil and groundwater erosion rates through the crack into a sewer pipe. Good agreement between experimental and predicted results on soil erosion rate is obtained. The analytical models indicate that the soil and water erosion rates are mainly controlled by the following factors: groundwater table or saturated soil height above the crack, particle size, particle shape, submerged repose angle, void ratio, and defect size.