Experimental assessment of the relationship between rainfall intensity and sinkholes caused by damaged sewer pipes

In: Natural hazards and earth system sciences: NHESS, Band 20, Heft 12, S. 3343-3359

Open Access

Abstract

Abstract. In several countries, the rising occurrence of sinkholes has led to severe
social and economic damage. Based on the mechanism of sinkhole development,
researchers have investigated the correlation between rainfall intensity and
sinkholes caused by damaged sewer pipes. In this study, the effect of
rainfall intensity on the formation of eroded zones, as well as the
occurrence of sinkholes caused by soil erosion due to groundwater
infiltration through pipe defects, has been analyzed through model tests.
The ground materials in Seoul were represented by weathered granite soil,
which is generally used for backfill sewer pipes, and groundwater levels
corresponding to three different rainfall intensity conditions were
considered. The ground level changes and ground displacements were measured
continuously, and the particle image velocimetry (PIV) algorithm was applied
to measure the displacement at each position of the model ground. The
results indicate that impeding the excessive rise in groundwater levels by
securing sufficient sewage treatment facilities can effectively prevent the
development of sinkholes caused by pipe defects.