Experimental study of the effect on soil erosion of using tiny gravel as bedding for defective sewer pipes

Abstract

Abstract The erosion of soil is the most influential factor contributing to the creation of sinkholes in urban areas. Soil degradation often takes place due to failures in sewer pipelines, when water flows from and to the adjacent soil through pipes defects. Soil deficiency surrounding faulty stormwater sewer pipes has been attributed to various reasons, including water infiltration and exfiltration volume or discharge, crack size, relative density, water heads, and the number of cracks. This paper focuses on the effect of using tiny gravel media as a protective layer to reduce the processes of soil erosion due to the faults in the wastewater system, which is done by means of a comparison of erosion mechanisms observed when using a protective tiny gravel layer and without. A local sandy soil was used, obtained from the neighbourhoods near the city centre in the Karbala governorate. Sixteen tests, separated into two groups, were performed to identify the differences in outcome between the two statuses, with a matrix of various influential factors to which erosion has been attributed used across the experiments. The outcomes demonstrated that using a tiny gravel layer as a protective bedding layer has an excellent effect on impeding soil erosion processes and, in particular, tremendous efficiency in reducing cavity formation of up to 95.4%. Furthermore, the findings showed an 18.25 times decrease in the total eroded soil, while the settlement of soil surface showed a 26.35 times decrease, allowing higher internal stability and reduced sewer pipe path deformation.