Cracked Underground Parking Lot... Residents Protest: "4-Meter Giant Piles Damage Apartment Foundation"

Gangnam Hanyang Sujain Emergency Committee Reveals Suguang Line Blueprint Analysis
"Thousands of 4-Meter-Long Giant Piles Piercing the Apartment Complex"

Residents of Gangnam Hanyang Sujain Apartment in Segok-dong, Gangnam-gu, Seoul, have once again demanded that the Suseo-Gwangju double-track railway (Sugang Line) tunnel route be redirected, arguing that the tunnel construction will reach the bedrock directly beneath their apartment buildings.

Crack in the underground parking lot of Gangnam Hanyang Sujain Apartment. Provided by the Emergency Response Committee.

The residents claim that the tunnel will run just 50 centimeters away from the building and that 4-meter-long "rock bolts," driven into the bedrock around the tunnel, will penetrate as much as 3.5 meters into the base of the apartment. Residents also argue that vibrations from the existing high-speed rail running beneath the complex have already caused cracks in the underground parking lot, and they are demanding a comprehensive safety assessment.

The Emergency Response Committee of Gangnam Hanyang Sujain Apartment (Emergency Response Committee) announced on the 30th that, after analyzing the National Railroad Corporation's Su-gwang Line tunnel design drawings, it confirmed that the rock bolts to be installed during tunnel excavation are 4 meters long. On the design, the distance between the tunnel and the apartment building is 0.5 meters. According to the committee's calculations, rock bolts driven toward the building would breach this gap and extend up to about 3.5 meters into the rock beneath the apartment.

Rock bolts are steel rods driven into holes drilled outward from the tunnel wall, designed to stabilize and prevent the surrounding rock from loosening or collapsing after the tunnel is excavated. In the widely used NATM (New Austrian Tunneling Method) in Korea, they are core materials for supporting tunnels alongside shotcrete (concrete sprayed onto walls). Since the bolts are installed in a fan-shaped pattern around the tunnel, the actual range of ground affected by the construction is broader than the visible tunnel cross-section.

A spokesperson for the Emergency Response Committee said, "The government has claimed at public hearings and other occasions that the route passes safely next to the buildings, but when looking at the actual drawings, thousands of 4-meter-long heavy stakes are being rammed harshly into the bedrock under our apartment and under the bedrooms where residents live," adding, "This is a design that damages the foundation supporting the building's load."

Another source of anxiety for residents is the presence of existing cracks. Photos released by the Emergency Response Committee show visible cracks in various columns and beams in the underground parking lot.

The committee considers these to be "shear cracks." Unlike fine cracks that develop as concrete dries, shear cracks occur when a structure is unable to withstand the forces applied to it, causing diagonal splitting or displacement. Residents point to vibrations from the Suseo High-Speed Railroad (SRT) and the metropolitan express railway (GTX-A), both of which already run beneath the complex, as the likely causes. However, the precise type and cause of the cracking can only be conclusively determined through a detailed safety inspection.

Once the Sugang Line opens, this section will have three large railway tunnels overlapping: the SRT, GTX-A, and the new tunnel. The National Railroad Corporation previously stated in online public hearing materials that the predicted ground subsidence would be 3 to 4 millimeters—well below the safety standard of 25 millimeters. However, residents have countered that subsidence of up to 150 millimeters has already been confirmed within the complex.

The public version of the environmental impact assessment indicated that the distance between the apartment and the tunnel was 8 meters, but the actual design shows a distance of only 50 centimeters, stirring further controversy.

The route change process has also become a point of contention. During the preliminary feasibility study in 2019, a route skirting the apartments along Tancheon stream was considered. Later, however, it was changed to a more direct route passing straight under the residential area. The Corporation has cited the need to avoid conflict with the Bundang Line as a reason why the Tancheon detour is not feasible. In July, the residents applied for collective conflict mediation with the Anti-Corruption & Civil Rights Commission.

The Emergency Response Committee is demanding three things regarding the Sugang Line: an alternative route that bypasses the complex, a detailed safety inspection and reinforcement plan to address existing cracks, and disciplinary action against those responsible for the current design. If these demands are not met, they plan to pursue legal action, request a Board of Audit and Inspection review, and mount large-scale protests.

The Sugang Line is a national railway project with a total length of approximately 19.4 kilometers and a budget of around 1 trillion won, targeted for opening in 2030. The Ministry of Land, Infrastructure and Transport granted initial approval in April for the Seongnam to Gwangju section; however, approval for the Seoul section has been delayed, as consultations on the environmental impact assessment have not yet been completed.

This content was produced with the assistance of AI translation services.