A sinkhole (ground subsidence) that opened in an apartment complex in Jungnang-gu, Seoul, was tentatively concluded to have been caused by an aging sewer pipe. (☞[Exclusive] A 3-meter-wide sinkhole in an apartment complex in Jungnang-gu, Seoul… "Identifying the cause")
According to the Jungnang District Office on the 11th, a sinkhole appeared at about 3 p.m. on the 8th in the parking lot of an apartment complex in Jungnang-gu. An expert dispatched for an emergency inspection found that the sewer pipe beneath the sinkhole was damaged.
It is presumed that soil was washed away over a long period by water leaking from the broken sewer pipe, causing the ground to cave in and leading to the sinkhole. The apartment was built in 1991.
However, the exact cause of the sinkhole requires further investigation. Resident A of the apartment complex said, "Last summer, water also leaked from the public sewer pipe right next to it, damaging a commercial building," adding, "It may not be only because the apartment is old."
Residents fear additional damage. The sinkhole was initially 3 meters wide and 1.5 meters deep, but it has grown larger and deeper to 5 meters wide and 3 meters deep. Resident A of the apartment complex said, "I'm worried because the sinkhole doubled in size in a day."
The Jungnang District Office asked the apartment complex to carry out excavation work to determine the exact cause and to check whether there are any additional broken sewer pipes.
Aging sewer pipes are a major cause of sinkhole accidents. Over the past five years, 80% of sinkholes that occurred in Seoul formed above sewer pipes that are more than 30 years old.
Song Gi-il, a professor in the Department of Social Infrastructure Engineering at Inha University, said, "Once sewer pipes are more than 30 years old, the risk of ground subsidence can increase due to aging." He added, "In summer, heavy downpours continue, which can act as a factor that accelerates ground settlement damage, so we need to be prepared."