Apartments Pierced in Seconds, Leaving Three Casualties... Retaining Walls Prove Useless

[Anchor]

The recent landslide in Geoje that resulted in casualties is a carbon copy of the Mt. Umyeon landslide in Seoul 15 years ago. In both accidents, massive amounts of soil and debris instantly crashed into the lower-floor units of apartment complexes.

Reporter Yoo Soo-Hwan investigates just how destructive such landslides can be and whether there are ways to prevent such disasters.

[Reporter]

Early in the morning on July 27, 2011, soil and debris from a landslide on Mt. Umyeon in Seocho-gu, Seoul, suddenly engulfed an apartment complex, claiming 16 lives.

Similarly, the landslide in Okpo-dong, Geoje, which left one person dead and two injured, occurred at 4:30 a.m., leaving residents with no time to escape.

[An Jae-hu / Resident of the Geoje Landslide Apartment: The soil burst through the house, debris was visible, and two people were pinned under the rubble on the first floor.]

The soil that struck the back of the apartment penetrated the first-floor units and broke right through the shared entrance. Water-saturated soil measuring 1 meter in width, length, and height weighs about 1.5 tons, comparable to a passenger car.

Flowing down a slope, it hits with the force of a speed of 11 km/h. In the case of a landslide, this means anywhere from several dozen to around 100 carloads of dirt pour down in an instant.

In particular, the recent landslide in Geoje occurred on the steep rear side of Mt. Guksabong, located directly behind the apartment.

Although rockfall fences and retaining walls were installed on the hillside, they proved useless under extreme heavy rainfall conditions like this one.

[Geoje City Hall Official: The retaining wall where the soil flowed down was only about 1.5 to 2 meters high...]

Experts point out that when apartment complexes are built by cutting into mountains, sufficient buffer distances must be maintained, and retaining walls should be installed differently depending on the characteristics of the mountain.

[Park Chang-keun / President of the Korea Authority of Land and Infrastructure Safety (Former Professor at Catholic Kwandong University): (For retaining walls,) it is necessary to strictly distinguish and design them based on whether it is a rocky mountain or a soil mountain, and if necessary, make the retaining walls considerably higher...]

[Lee Young-joo / Professor of Fire and Disaster Protection Engineering at Kyongil University: It is (advisable) to secure sufficient separation distances and ensure spaces that can provide physical buffering.]

During the Mt. Umyeon landslide, a large amount of water-laden debris also poured into apartments and residential areas, but there were no facilities to stop it.

According to Ministry of the Interior and Safety statistics, out of 160 deaths and disappearances caused by heavy rain over the past 10 years, landslide casualties accounted for the largest share at 75 people.

(Photo: Yonhap News)
(Video Reported by Kyungmun | Video Edited by Seeun)
※ Please note: This article was translated by AI and may contain errors.