Suffosion holes as the results of a breakage of a buried water pipe

Abstract

The result of a breakage of a buried water pipe is the water movement in soil, which can cause that fine soil particles are washed out from the solid matrix and transported through pores (suffosion process). It is widely known that the most hazardous suffosion effects in urban areas relate to water-engineering structures. Holes, that can form on the soil surface by water outflowing after a failure of a buried pipeline (suffosion holes), are in different shapes and sizes. Recognition of factors influencing holes shapes and sizes would facilitate the prevention of hazardous suffosion effects connected with failures of water distribution systems. In the range of the presented article, the influence of selected parameters on the dimensions of suffosion holes was analyzed. The basis of the analysis was results of laboratory investigations of the controlled leakage from a buried water pipe. The vast majority of values of suffosion holes areas, selected according to area of leak and hydraulic pressure head in a pipe, occurred normally distributed. The tendency of average area of suffosion holes to be higher with rising pressure head in a pipe was clearly visible, but we were as yet unable to select one regression model fitting measured and calculated data better than others. Moreover, no tendency was observed between the biggest probable area of suffosion hole and pressure head in a pipe.