Osan Retaining Wall Collapse Investigation Extended by 3 Months..."Additional Collapse"

Retaining Wall Collapse in July Claims Life of Man in His 40s
Heavy Rainfall Causes Ground Cracks, Making Detailed Investigation Inevitable

The investigation into the cause of the reinforced earth retaining wall collapse that occurred in Osan City, Gyeonggi Province, last July has been delayed by three months from the original plan. The Central Facility Accident Investigation Committee for the Osan Reinforced Earth Retaining Wall Collapse announced on the 19th that "due to additional collapses at the site and heavy rainfall, a more detailed investigation is required, so the investigation deadline will be extended from September 20 to December 20."

Since the kickoff meeting on July 21, the committee has conducted two on-site inspections, five general meetings, and two hearings with related parties. The committee has focused on determining the cause of the collapse, reviewing design documents and analyzing 3D video footage to discuss possible scenarios. However, unexpected variables have arisen.

On July 16, a 10-meter-high retaining wall at the Gajang Intersection overpass in Osan City, Gyeonggi Province, collapsed onto the road, covering two vehicles. Firefighters are conducting rescue operations. Photo by Gyeonggi Provincial Fire and Disaster Headquarters

Although the initial safety measures at the accident site, such as installing monitoring devices and stacking sandbags, had been completed, ground cracks and displacement occurred after heavy rainfall. During the second stabilization process, an additional collapse took place, making it urgent to secure safety at the site. Accordingly, the committee plans to conduct a precise investigation into the cause by performing three-dimensional structural analysis that reflects sample collection and on-site test results, as well as verifying collapse scenarios.

Kwon Og-yun, chairperson of the investigation committee, stated, "We are keeping all possibilities open regarding the cause of the accident and are thoroughly examining even the smallest clues from multiple angles. We will objectively determine the cause of the accident and establish measures to prevent recurrence by comprehensively reviewing the design documents, ground surveys, and various structural analyses and verification results."

Previously, on July 16, a 10-meter-high retaining wall of the overpass toward Suwon at Gajang Intersection in Osan City collapsed, crushing a passenger car passing on the road below. A man in his 40s who was driving the vehicle was killed in the accident. The retaining wall in question is known as a "reinforced earth retaining wall," a structure in which reinforcements such as steel bars are embedded in the soil so that the earth itself can withstand pressure like a wall.