Concerns over safety have intensified following the discovery of rebar omissions in the GTX-A line construction and repeated ground subsidence near the Naeseong Underpass in Busan, which opened just three months ago. Both construction sites involve deep underground work, with depths exceeding 40 meters. As urban congestion increases, the frequency of deep underground projects has risen, yet the regulatory framework has not kept pace with international standards.
As of May 21, the construction progress of the Yeongdong-daero underground complex development project is at 57.91%. This large-scale underground infrastructure project has a total budget of 1.7 trillion won.
Errors in construction were identified late at the Samsung Station site, where rebar omissions were confirmed on the fifth underground level. Out of 218 columns in the entire platform, 80 were found to be missing rebar, with 50 of those failing to meet design standards. The primary rebar was supposed to be installed in two rows but was incorrectly placed in one.
The issue is compounded by the fact that the Ministry of Land, Infrastructure and Transport only confirmed the omissions last month, despite Hyundai Engineering's initial report to the Seoul city government in November. The city explained the delay by stating, "We finalized the reinforcement plan in April after checking the applicability on-site."
The city reported the issue to the Korea National Railway Authority six times, but the authority claimed it was not fully aware of the situation. An official stated, "While some related information was included in the reports by section, it was not considered a separate report." The GTX-A Samsung Station section is being constructed under the authority's oversight.
In Busan, ground subsidence has occurred multiple times at the entrance of the Naeseong Underpass within a month. The city is investigating the possibility of inadequate backfilling after deep underground construction using ground-penetrating radar (GPR) but has not found any direct signs of abnormalities. Concerns about construction errors and insufficient post-construction management are being raised simultaneously.
Experts point out that the current regulatory gaps are increasing the risk of accidents. The Seoul Institute published a report in September 2022, stating, "There is a general absence of regulations and standards related to deep underground construction."
Since the GTX project began, the demand for underground urban rail and deep roads has surged due to a lack of available land and challenges in expanding surface infrastructure, making deep underground utilization an unavoidable choice.
However, legal and regulatory frameworks remain in their infancy. A special law on deep underground construction proposed in 2020, which included penalties for safety and environmental violations, was not passed and has since been discarded. Currently, related laws are scattered, with only partial adherence to the Integrated Development of Underground Railways Act and the Underground Safety Act.
Deep underground construction occurs at much greater depths than typical underground projects, necessitating a more precise approach due to varying ground conditions, groundwater flow, and hydrogeological characteristics. However, existing underground environmental impact assessments and safety management plans are primarily designed to prevent ground subsidence and do not adequately reflect the characteristics of deep underground construction.
Comparing with international practices highlights a significant gap. Japan enacted the "Special Measures Law on Public Use of Deep Underground" in 2000, establishing systematic standards. During the construction of the Tokyo Outer Ring Road, they implemented a system for public disclosure of progress and long-term safety monitoring.
The Seoul Institute recommends that project owners regularly check whether monitoring plans established during the design phase are being implemented as intended on-site, and take corrective actions as necessary. Suggested measures include establishing a real-time monitoring data sharing system, regular verification by third-party experts, and the introduction of a resident participation monitoring committee.
* This article has been translated by AI.
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